Depends on the person. I have many games that I will never play, and have desire to. But the history behind the game, or the people that made it are interesting enough to me that I want to own a part of it.
Space is probably a limiting factor for most people. I have a dedicated game room in my house, which not everyone has, so space is not a deciding factor for me.
I would image the whole "collection" aspect will become less popular now that digital is a growing trend.