You must be one serious power user, because Linux in the 90s was so unusable it gives me a migraine just thinking about trying to use it back then.

That really didn't change until well into the current century.
Setting up PPP dial-up for Internet access was kind of tricky indeed. But I grew up on Unix which was a first real OS I touched after cutting my teeth on 8bit computers.
Windows had a certain edge on Linux in early 2000s, mainly due to Office but after equivalent Open Source software emerged soon, it was no brainer to go back.
I was never into gaming so that has not been a factor for me (Windows dominate the market).