Flash has lost the race for building standard mobile apps and Adobe knows it:
Looking forward, Adobe believes that Flash is particularly suited for
addressing the gaming and premium video markets, and will focus its
development efforts in those areas.
Then, there's the community and transparency to its users. Adobe has been notoriously bad at this. Obviously W3C is wide open to anyone, so it's wholly transparent and developers can know what to expect. Having said that, knowing what to expect doesn't automatically equate to proposed standards not changing frequently or the working group to be a well oiled machine, but all is transparent, while Adobe's somewhat of a black box.
Now that I've gotten somewhat off track with my thoughts..