What is that forked version was on over half the devices? What if that forked version was mostly a way for developers could protect themselves from thieves. What if customers knew that apps in this forked version's app store were unlikely to be scam apps that stole your data, were not what they said they were, or had viruses in them?
Samsung could do just that and likely ruin the possibility that other Android-based vendors of making any advancement and Samsung could do it without resisting access to any regular Android app if the user still insisted. It would essentially be no different than getting apps in and outside the Mac App Store and using Gatekeeper to help protect your device.
Note that Samsung already has APIs for their Galaxy Note's Wacom digitizer. Not exactly a smoking gun but it could be seen as the first brick.
If wen the hand strikes midnight my prediction has failed to materialize I insist on the original payment. Don't let me go into the New Year squelching on a bet.