I disagree but more on the basis that it's because a lot of autism simulators like DF, underrail, CDDA, etc, do a piss poor job at introducing systems gradually and/or having a comprehensive way for the player to engage with each system on their own time.
I think it just stems from those autistically detailed games being made by very passionate autists.
Don't get me wrong, I love games like DF but goddamn if I hadn't learned the games in that genre when I was a teenager with too much free time I couldn't possibly be asked to either read 20000 textboxes or spend 60 hours in frustration doing trial and error, I don't have time for that shit now.
Another reason I disagree is because if it's not either a hyperfocused, narrow experience or a (properly structured) bundle of complex systems, you end up with shit like skyrim.
Yeah, there's a lot to do, but no, none of it is that interesting or engaging. I mean, the only aspect of Skyrim skill-wise that's remotely interesting is the alchemy skill but purely because you can do dumb shit with it through resto-loop and the like.
Sandboxes (and to a lesser extent certain rpgs/lifesims) should be about players utilizing interesting & engaging mechanics to craft their own story. DF lets you break the game if you want, so do so many others, and they offer a ton of ways to go about doing that.
Taking away the complexity in turn vastly limits the amount of tools the player has to create their own unique & interesting stories.