Define lots? You are describing someone who: 1/ has spent many years building a steam collection (has $$$) and 2/ has a collection of console-playable games but never bought a console to play them. (Suggests doesn't have $$$). and 3/ doesn't already have, or desire building, a SFF upgradable PC?
Like, the sweet spot is they have to: 1. have $$$ of games, 2. have $1200 to spend on a second PC and 3. not have, nor desire to have, an upgradeable SFF PC.
$1200 is a 5070ti or a 5080 (just). We know they have a PC already (they have $$$ steam games). If I have a PC already and I play games, and it doesn't have a 5080, then I'm spending my $1200 on the 5080, not a living room console. So, now we're talking about someone who either has a 5080, or plays the kind of casual games that don't need a 5080. My experience is that those kind of games aren't great on a TV and a joystick. I'm not playing Factorio, Civ, Rimworld or Citizen Sleeper on a TV with a controller!
I've got quite a steam collection, but they are all non-console games. That's the distinction for whether I bought it on steam or for a console.
Is there a large demographic who bought console games on steam because they don't own a console?
Anyway, valve themselves have the demographics, so presumably they see a target market. I just don't know what it is! =)