I’m more surprised that many people are still using stadia to be honest. I thought Google have been winding it down for some time.
As a bit of a "privacy nut", I'm more careful about what I leave on other people's servers than most people I know, though, so I acknowledge I'm not anywhere near the median on this.
My understanding is subscription services from Microsoft, Sony and Epic give free games every month which you own once you have downloaded them. By contrast Stadia is a subscription which gives you the right to play games on their servers but you have to purchase the games first, and if the servers get switched off (as will soon happen) all you have afterwards is a dead controller and your memories.
They did give me my money back, at least.