And yes I know it's marketing, but if what they say in their LTT[1] video is true, then GPU driver optimizations are apparently a titanically tedious clustertruck, which... honestly, considering all the weird API's and graphical schenanigans of games past, I concur.
I think if they didn't release now, even with all the bugs, they were never going to. If it actually makes a profit, they'll finally have in incentive to invest enough that it even COULD catch up.