Honestly it’s gonna take a while to cycle the existing 1000 and 2000 cards out of the market, they were already both pretty good. 
I think mid-range stuff that works with the older cards will stick around for the budget-conscious gamer for some time.
MSFS definitely has some … idiosyncratic points of slowness in its system but honestly it’s inherently a bit different from most games because it’s doing a lot of number-crunching on the atmospheric simulation, and has a bigger scale that most non-flight-simulator games. So it is inherently more CPU-hungry, and some of that code is well-optimized over threads but some of it is not. I expect MSFS will continue to improve on that front, but that single-core performance for the main thread will continue to be critical for a smooth experience on both “pancake mode” and VR.
If getting a new card, something to consider is also VRAM – MSFS scenery is very VRAM-hungry, especially running at higher graphics levels, so don’t skimp. An 8 GB card is not overkill at all for MSFS, I have to tune a little to keep from overflowing VRAM in Los Angeles which is a busy area.