So true. For the OP, I would consider the decimated XP 3rd party developer scene. Thranda, a major 3rd party developer for XP, is on record saying their sales are down immensely since the peak XP 11 days, and that a lot of people have left XP:
I won’t be disclosing sales numbers. But what I CAN say is, that they used to be many times higher… before MSFS2020 hit the market. We have published 10 planes, roughly, since then… and not even with 10 more planes on the market, have we seen a month in sales like when we published the PC6 four years ago. Not even with significant discounts on our products during entire months of sales. It seems like a LOT of customers have left X-Plane. And this is very alarming, because it’s an intensifying feedback loop. The less viable it is to make planes here, the less interest the market will have in X-Plane.
Note that the PC-6 was released by Thranda for XP 11 in 2020, before MSFS 2020 was released.
In addition, the flight dynamics for XP 12 are no longer better than MSFS 2024. Various real life pilots have commented on the flight dynamics for MSFS 2024. See this page for multiple comparisons by real life pilots who prefer the MSFS 2024 flight dynamics over XP 12 flight dynamics: https://www.avsim.com/forums/topic/654326-msfs-2024-flight-dynamics-and-groundwater-handling-thread/page/9/
Here is V1Simulations, a real life A320 pilot, rating the Fenix in MSFS 2024 better than the Toliss in XP 12 with respect to flight dymamics and other areas of comparison: https://www.youtube.com/live/UTOeK4Zn630?t=8280s
Finally, the GA avionics in XP 12 are so far behind MSFS avionics. The G1000 NXi, G3000, G5000, and G3X in MSFS are so good, you can’t even buy a better payware version at the moment than the ones in MSFS. Plus Working Title did a very good job on the GNS 530 and GNS 430. And for MSFS 2024, Working Title has done the Honeywell Primus Epic 2 and Universal UNS-1. There is a huge gap between the default avionics in XP 12 and MSFS 2024, it’s too large of a gap, IMO.
As for the graphics and terrain at ground level when no customer scenery is used, when everything is working normally for MSFS 2024, MSFS 2024 graphics at the ground level looks like its 7 years more advanced than MSFS 2020. MSFS 2020 graphics at the ground level look like its 8 years more advanced than XP 12. So MSFS 2024 graphics look like its 15 years more advanced than XP 12. 15 years is a lot, that’s 2 generation of graphics, it’s like the difference between a Playstation 4 and Playstation 2!
This is the ground scenery that MSFS 2024 can generate, plus the performance is generally good with most high end computers (not everybody is getting better performance in MSFS 2024, but many people are): https://www.reddit.com/r/MicrosoftFlightSim/comments/1h3igen/places_ive_been_over_the_years_revisited_in/
I have my doubts that even the next version of XP - XP 13 - can match the graphics that MSFS 2024 can generate at the ground level, as per the photos in that Reddit thread above.
Now some people will say this is a flight simulator and not a ground simulator. But how the ground looks is important if you are doing low level flying, which includes bush flying, helicopter low level flying, and even stuff like the crop dusting mission in MSFS 2024. Not everyone is flying airliners at high altitudes, some of us also enjoy low level flight in MSFS 2024.