The golden handcuffs are your ability to ship Android's userland (including access to use of trademarks and Play Store). If Google shuts you out, you're out. Ship all the linux kernels you want.

Technically, you can probably ship something based on pure AOSP, but your competitors will have had pre-AOSP access to the code for multiple months and there are no guarantees that AOSP even works without Google's magic proprietary mojo. CyanogenMod had to develop the missing pieces when Google sent their C&D over the proprietary bits. I would suspect defensive things designed to make it more difficult for Amazon to leech AOSP are either present or coming soon particularly with the rumors that Amazon is working toward introducing a phone.

> there are no guarantees that AOSP even works without Google's magic proprietary mojo

What do you mean by this? If you mean in the market, it can work. Amazon's devices are proof. If a manufacturer is shipping just AOSP, it needs to have a working complement to Google's suite of apps or it needs to have a different value proposition altogether.

> CyanogenMod had to develop the missing pieces when Google sent their C&D over the proprietary bits

What "missing bits"? They were shipping Google's suite of proprietary apps on top of their AOSP-based ROM and they stopped after the C&D.

Once Google's proprietary stuff was deleted, it was not possible to provision a phone (until the FOSS alternates for things like Provision.apk were developed). I can't remember if you got bootloops or what. There were other problems, too. I think AOSP has been friendly toward patches for that sort of thing... ensuring AOSP without gapps works just wasn't one of Google's requirements (at least early on--it may be now for all I know). Not that you can really fault them for having different priorities.

The anti-fork rules concern Google's support and applications for devices, not the source code of the OS itself.

Amazon has forked Android, but by doing so they aren't allowed to use any of Google's apps in their devices.

The "anti fork" agreements Google has with OEMs are not public, but some terms of these agreements were made public in a lawsuit involving Skyhook: http://www.theverge.com/2011/05/12/google-android-skyhook-la...

What it boils down to is that Google has a final approval over any Google-logo Android device. For phone OEMs, this looks like absolute and arbitrary control by Google, but, in reality, it's a three-way negotiation between the OEM, Google, and, in the US, the carrier controlling the channel for the product, with any one of them able to sink a product before it reaches the market.

Google has never seen fit to make licensing terms for Google's ecosystem apps (Maps, Play, etc.) transparent. That's a pretty sharp contrast with Android as an open source project, and even with the way Windows Mobile (not Windows Phone) was licensed.

So Android is open, on the one (AOSP) hand, and un-transparently proprietary on the other hand. That leaves an obvious market opening for a truly open OS. But, so far, Tizen, Open WebOS, or any other possible contenders have been insufficient and/or under-developed. Maybe Canonical will get it right.