It might be. On monitors the difference between a 120hz refresh rate and 144hz refresh rate is about 14ms between frames. Some people (claim) to tell the difference.
Correct, Google has all the leverage to dictate what non-Apple smartphone manufacturers sell. Moving to Fuchsia would be expensive for everybody involved. Google is developing a new OS. Chip manufacturers will have to write new driver code. Cell manufacturers will have to integrate a new system. Everyone loses the work they put into the Android Open Source Project and their private branches of ASOP.
With all this cost, who's getting the upside? Google is clearly getting the lion's share.
I think Google legitimately believed nothing was wrong with their implementation of Java and that implementing a language with so many developers was a smart move.