They didn’t start marketing office chairs to gamers before 2006. Many people I knew used an office chair for PC gaming and their couch or a futon for console gaming. Kids also used those tiny little chairs that are shaped like a little L or bean bag chairs.
Which is hilarious because most “gamers chairs” are just branded overpriced regular chairs. The quality is subpar compared to an equally priced normal chair. It’s just a moron tax.
Go look up racing sim seats. Then look up a real seat you’d put in your car. Real seats will often be much cheaper than a sim racing seat. One company even sells a sim kit that includes a seat that is clearly a normal seat from a different company and marked up.
You’re better off buying “normal” products than gamer versions a lot of times. They just add flashy colors for the most part.