I 100% agree.
Developers aren’t using new technology yet. Probably textures were just ported from FSX without knowledge of PBR, lightmaps etc.I don’t know what it is and sure there are a few exceptions (eg JF PA-28) but 1/2 of the planes are so ugly that I rather like the cockpits in X-Plane. By a mile in fact.
The second problem is that airplanes in MSFS look better from the external view than from the cockpit. That’s a weird problem and I think it is because the resolution of the cockpit textures is ridiculously low.
The good news is that in the next years it will improve when developers have learned how to make planes for FS2020.