What's the deal with the Android Open Source Project? You can go to source.android.com and clone it. And the license is Apache! So you can make your changes, install them on your own phone, and sell it! You don't have to share with Google!
The Android kernel is Linux; that part is covered by the GPLv2. The Apache license applies to all the Android-specific stuff.
But somehow this isn't happening. There is exactly one commercial offering of AOSP code on a non-Google-licensed device: the Amazon Kindle Fire (which I had no idea was Android). Frankly, nobody buys a Kindle to have an Android device.
How does Google keep everyone in line, and sell its licenses? What keeps every phone maker from cloning their own fork of AOSP?
Ars Technica's Ron Amadeo wrote about this in 2013, and the article was recently updated: arstechnica.com/gadgets/2018/07/googles-iron-grip-on-android-controlling-open-source-by-any-means-necessary.
Google started AOSP a few months after the first iPhone came out in 2007. Google clearly understood that mobile devices were the future, and that it would be all too easy for Google search to disappear. Google was probably paying Apple a lot more than they were happy with to have Google Search be featured on that first iPhone.
Android was open source because Google had no hardware platform. They had no mobile presence whatsoever. So they priced it to move, so to speak. Non-Apple alternatives at the time were the Blackberry OS and Symbian, started by Nokia. (Remember Symbian? Me neither.)
Today Android has an 80% market share. So maybe Google regrets the open-source thing?
From the beginning, not everything was open source. Google had their proprietary apps:
Some of these may have equivalents in AOSP, but they are more-or-less abandoned. And you can use a web browser to get at most of the above, but that's not as slick.
If you have an Android phone, note the Google Search app. You can open Chrome instead, and go to google.com, or even create a desktop shortcut to google.com. But then you don't get the Google Assistant, or any voice response, or other handy features. (You do get to open selected search results in new tabs, which is oddly missing from the Google Search app.)
So this left Google with a carrot to phone makers: "license with us and you get all this cool stuff". The licensing is believed to be pretty cheap, if not free; the point is that it comes with strings. If you license with Google, you must use Google's flavor of Android. No open-source improvements allowed.
The AOSP Music player was a plain-vanilla player. The Google Play Music app is quite different, with hooks into streaming services, and places to buy music.
AOSP has a Calendar app too. But it doesn't sync to the Cloud. The closed-source Google Calendar is much slicker.
Google even has a proprietary swipeable keyboard app.
Ditto the Messages (SMS) app and even the Camera.
Still, for a phone manufacturer to create its own clone of AOSP, so far all it has to do is update the various Google apps. Amazon did that. Samsung has its own version of all the Google apps. How hard can it be?
Google has a few more hoops.
First and foremost, if you as a manufacturer have a license to manufacture Google-licensed Android phones, then you are probably a member of the Open Handset Alliance. Getting a license without being a member of the OHA might be possible, but it's not clear anyone has ever done it. And a big part of your OHA agreement requires that you will not manufacture any non-Google-licensed phones. That leaves a phone company with a big problem, as most phone sellers are not their own manufacturers (Samsung is).
In China, stock Google Android is not allowed. Alibaba has an AOSP clone, called Aliyun. Acer was hired to make Aliyun phones, and Google told them to stop. Acer did. This may have changed; a more recent Google ToS says
Devices may only be distributed if all Google Applications authorized for distribution in the applicable territory are pre-installed on the device.
Since no Google Applications are authorized in China, Acer may now be ok. It is not clear whether Acer is in fact making Aliyun phones, however.
Amazon had to look very hard to find a manufacturer for its AOSP Kindle Fire. But then, Amazon has resources.They finally found Quanta (not exactly a familiar name).
Samsung has the alternative apps in place, and is probably the only Android phone maker in this position. So they could quit. But that would mean that Samsung would have to stop making Google-Android phones immediately. If a future Galaxy S-10 is AOSP-based, then no more sales of Google-Android S9's.
Also, customers like the Google apps.
Skyhook has built a competing location-service app; like Google's when GPS is off, it is believed to determine your location from nearby Wi-Fi access points. Some phone makers tried to drop Google's location service (built into the Android infrastructure; it is not an app) in favor of Skyhook's. Google made them stop. Skyhook's lawsuit is still pending. (Skyhook is also suing Google for patent infringment.)
Google has one more line of defense: you must license the Google version of Android if you want access to the Google Play Store, that is, the app store. Amazon has built their own app store for the Fire Kindle. Nobody else has tried.
It's not even as simple as contacting 100,000 app devs and asking for their app to be included in your store too. Most apps use at least one Google proprietary API. That means most apps simply will not run on a vanilla AOSP device. Here are a few hard-to-go-without APIs:
There's even a games API, Play Games, that most game devs end up using.
One final sting: most of Google's APIs are in fact supported on iPhones. So using Google makes things a lot easier for devs; often it makes the Android and iOS versions almost the same.
Amazon maintains a list of alternative APIs for Kindle Fire devs at developer.amazon.com/docs/app-submission/migrate-existing-app.html. They've had their work cut out for them.
Bottom line: between the Google apps, the manufacturing rule, and access to the App Store, nobody dares to leave the fold. Not even Samsung, who is clearly best positioned to do so (Samsung does have their own App Store. It is annoying as heck, as their store does app updates independently of Google's.)
[Roughly "VES-dae-ya"] Why the EU thinks Google is engaging in anticompetitive behavior may now be a little clearer. The EU complaint focuses on two primary things Android phone makers are forced to install:
Around 2000, Microsoft was sued by the US Dept of Justice for antitrust violations because they required manufacturers of Windows computers to install Internet Explorer. Microsoft agreed to allow competing browsers, while at the same time trying to integrate IE into the desktop. (They later abandoned that plan.) Sun workstations, meanwhile, were all shipped with a browser made by Sun. (Mosaic was also available. That's not Mozilla; Mozilla was named because it is the Mosaic Killer.)
For a manufacturer to require the installation of B when a customer (the phone maker) wants to install A is called tying. It is generally forbidden under antitrust law.
Under US law, the government must not just show that Google's competitors were harmed by Google's tying rules. They must also show that consumers were harmed. This can be difficult.The FTC considered action against Google in 2012, following the recommendations of an internal committee, but Google was a major supporter of the Obama administration.
One theory is that Google is in trouble because they made Android open-source, but have schemed mightily to prevent meaningful adoption of AOSP on phones. This isn't quite true; Google would be in trouble if they simply licensed Android as a commercial project.
Apparently the EU received multiple complaints from US phone manufacturers (are there any?) objecting to Google's terms. The usual complaint was that it was the App Store (Google Play Store) that was the absolutely-must-have app, and that to get that, the vendors had to install Chrome and Google Search.
So the EU case really is about loosening Google's tight grip on Android, but not necessarily about unlocking AOSP.
DuckDuckGo greeted the EU fine announcement positively.