The issue is that the MS ecosystem has too many pieces of middleware holding everything together. Like I always say, it’s like a Rube Goldberg machine. You have a series of multiple, loosely connected pieces of software / services that all need to be installed, updated, logged in, and running correctly. The first does something, which triggers the next, etc until the sim finally launches. And if anything in the chain is broken, you can’t load your sim and you just get some cryptic error message that means nothing.
With Steam, you have Steam itself and the sim. There’s nothing in between. No DRM locked game files (outside of DLC which is normal). It just works.