Look at it like this:
These extensions will never solve the problem they're designed to solve. They will not solve it because they're largely unimplementable (as is evidenced by the refusal of at least one vendor to implement them on technical grounds, and by the low activation rate of another vendor). These extensions should not have moved beyond the proposal and draft stages because clearly consensus on them was not reached, and technical issues where not addressed. But because they're now in community approved status, they cannot be reworked to make them adequate tools to solve the problem. And because they're in the registry, no other extension can be introduced that would actually address the same problem.
I'm very unhappy about limbo extensions like this. I think they're bad form, and they're bad for WebGL as a whole.