Samsung owns 65% of the Android market.  Why do we still call it the Android platform?

Why doesn't Samsung do a full move and fork Android, make it their own?  I believe they have tried that and showed their results to Google at CES, however I speculate that Google didn't think much of their strategy. 

The thing is, Samsung has a significant amount of power and can use it to make their platform better.  Interesting choice of the word "platform" - that is usually reserved for unified hardware and software solution, such as the Mac or iPhone.  Amazon has a platform with Kindle Fire, why not Samsung?

Having one platform in the Samsung/Android world would make it much easier for developers, as long as Samsung would take the same care Apple does to ensure their OS versions work seamlessly across a wide variety of hardware.

If I were the head of Samsung I would direct my product team to fork Android and build my own platform.