I'm not that sure that's the limiting factor these days. If Sony/Microsoft/Steam can be trusted to remember what I have in my library, I only need enough space

I'm not that sure that's the limiting factor these days. If Sony/Microsoft/Steam can be trusted to remember what I have in my library, I only need enough space to store the set of games I'm currently interested in. And with sufficient bandwidth, I can swap that set around very easily. Especially if I can control what I have installed via a mobile device -- think I might want to play a game tonight? Kick it off during my lunch hour, and it's ready and waiting when I get home.