You forget that MSFS2020 is the ONLY flight simulator so far with a marketplace that Microsoft makes money with it. That’s okay and I accept that too. I’ve already left quite a bit of money there. And Microsoft earned. For add-ons that were from Microsoft itself, the full sum, for those from third-party developers, up to 30 percent, I’ve heard. And I’m sure many others have already invested a lot of money there. Competitors like X-Plane, P3D etc. do NOT have a marketplace with an additional source of income. That’s why they have to keep releasing new versions because it’s the only way for them to finance the development.
There was also no marketplace in FSX or any of its predecessors. At that time, only physical copies were sold, which had to be produced and distributed at great expense. Today there is the internet. The “production costs” are negligible in comparison.