If you are saying "developers should be forbidden from working on newer generations until everything is finished on older generations" then the overall rate of progress would drop dramatically, since it's generally a lot faster to write code for a new feature designed to work across all the generations supported by the driver than to only look at older parts. In this case hyper-z and the backend work are pretty interdependent IIRC and both were happening at the same time, so it seems to make sense that Jerome would have had an Evergreen card in his system when it all came together.
Anyways, key point here is that most of these features are implemented for multiple generations at the same time, and it's luck of the draw which generation starts working first. If you assume conspiracy or lack of care for older hardware each time that happens you're going to be whipsawing between happiness and misery for no good reason. You probably owe the developers a bit of an apology.