Worth noting that Steam doesn't track playtime for non-Steam games. So this doesn't include Minecraft, Retroarch, or anything purchased through Itch, GOG, or Epic.
Emulation Station might, since a lot of people use it as a frontend for their emulators. Since ES runs in a separate window while you play, all the time spent playing emulated games would all add to ES's total.
I think that's what we see and may be misattributing of a small active subset that is very technical and invested.
It's on the steam store. I'm sure many people buy and play, and don't ever read or write on a community like this. They're "invisible" here, but impact if not dominate the playtime ranking.