What's the difference if they're just standing in the basement providing enjoyment?

I currently own a Doctor Who (bought for 640,- €) and an Indiana Jones (2000,- €). Both are just big clunky boxes causing expenses (spare parts, power, part of my apartment rent for the room they need). Bad investment, it seems. I'm keeping them because I like to play them; they provide no further benefit than fun until I sell them (which I don't intend to do).

Another approach - which one is more valuable?
As I spend more time playing Doctor Who, obviously that one is more valuable. Hm, strange result, let's try another way of seeing it.

If I had to spend 50 ct. for each game...
Doctor Who: 3000 games --> 1500,- € saved minus 640,- initial cost --> still 860,- saved. Woohoo! Great investment!
Indy: 700 games --> 350,- € saved minus 2000,- initial cost --> -1650,- Oops. Obviously a bad idea....