I've been in a number of threads with people talking about the various Steam sales. The Holiday Steam sale, and the Summer Steam sale. They talk about how last Holiday they spent $250 buying various games on Steam. They have hundreds of games on Steam, yet have only actually played a baker's dozen.
Yet... They are compelled to buy more. We're talking about digital downloads, that can never be resold, and are tied to one specific Steam account, yet it actually seems that some people seem to "collect" Steam games. It's the strangest thing...
I think it's just primarily a psychological thing. Some people get satisfaction from finding a good deal, and buying the good deal, even if it's for an item that they aren't even going to use for many months, if ever. I used to collect Super Nintendo carts (and still do on occasion), but collecting something that is nothing more than a lease with Steam, seems a bit questionable. There is no guarantee that Steam will exist forever. So, it's really like when we are buying games on Steam, we are leasing them for the amount of time that Steam exists, which isn't guaranteed by any measure.
I've been caught up in the madness as well. I have so many games floating on my backlog, yet when I find a screaming deal for $5, I feel like I have to buy it, even if I know deep down inside that I probably won't play it for 8 months or more. It's a strange thing really. Doing it with SNES carts is one thing, because they can always be sold to somebody else.
It's a weird phenomenon.