My thoughts are frame generation is good in theory, but not really practical for the sim, nor do I have any desire for it period because I wouldn’t need 100+ fps. Give this video a look.
Notice that on a 4090 he gets about 50fps without FG. When I get that (albeit on a lower end card at reduced settings), things are buttery smooth. When he turns FG on, yes frame rates are much higher, but the base frame rate is low enough to make artifacts fairly noticeable. Personally I would prefer to fly without FG at a smooth 50fps without artifacts over 100+fps with artifacts. Since it’s unlikely I would notice much difference in smoothness either way, 100+fps in general is overkill for me. This isn’t an action or competitive game. I would even go so far as to reduce settings to increase my frame rates vs FG if I felt performance was low.
So in the context of looking at only the rasterized performance in the sim without FG, my vote is the 7900xtx and is what I’m getting for my next upgrade unless the next series cards are coming out by then. It’s cheaper, trades blows with the 4080, and I think edges out in the sim specifically. I would only consider the 4080 if going VR or maybe better ray tracing support.