I agree that it might have been possible to get this done much earlier, but I don't agree with your premise that "done is better than perfect". Lots of people complain that while C++ packs a lot of features, it's ugly and everything is mismatched, as it seems. I don't necessarily agree completely, but a number of things are just annoying (e.g. how do you overload pre- and postfix ++? operator++() and operator++(int), where the dummy int doesn't do anything. Beautiful.)

I believe that even at the cost of speed of progress, getting this kind of impactful feature right is worth the trouble, especially since therr are already other possibilities for using coroutines in C right now, although they're not nicely fitted into the language.