Because nobody made a Steam Deck until 2020. Everyone plays video games now and have for years, and unless you have a console, the only way to play 99% of video games is using Steam’s windows version or a specially adapted Linux .
Don’t get me wrong, the moment that Windows 11/12/etc. outright requires logging into a Microsoft account (Protip: As of this writing, using the email “no@thankyou.com” and submitting a blank password forces Windows 11 to let you make/log into a local user account) to use it, I’ll be installing Steam OS on my OneXFly, and it’s why I don’t use my “free” upgrade to 11 on my Windows 10 gaming desktop. I just don’t think you realize how big a deal compatibility really is for gaming.
But I remember we did it. “Okay, Brian, the record’s five. The record’s five… Okay ready? Go!”