I do play my games and even if I didn't, people don't throw away the movies they watched if its their favorite film, their favorite books, or a collection of CD's they keep in their car just because they aren't listening to that CD. My consoles don't smell and I can still remember why I purchased the game I forgot I owned. Even so, if I were to hold a game in my hand that I forgot I owned then it may come at a surprise or its part of the reason to why I enjoy video games period.
I think you have the right of it. Physical items are a sort of memory totem. It's like people who smell a certain perfume or hear a certain song and remember a specific experience in their life. Looking through my game collection, I'm taken back, not just to the games that I played, but also to the time period that I played it.
Like, looking at Lufia 2, I remember staring at it at the local Toys R Us when it was about twice as expensive as every other game there (I think it was something outrageous, like $95). I remember playing it while sitting on my girlfriend's (now wife's) couch in her tiny apartment and getting frustrated because I was in the big random dungeon with no way to save and I had a physics class coming up
I see 1080 and I remember the time I brought it in to show my producer at the game company I was working at (making a snowboarding game), which he dismissed a crap after playing for about 30 seconds.
My Japanese copy of Mario Kart 64, I remember paying a local importing store about $150 for it and it included a special N64 controller that I made mine and mine alone - nobody else could touch that controller when we played Goldeneye every Friday night.
Or Utawarerumono 2, where I was so into the games that I played the two games back to back for about 8 hours a day for two or three weeks - I did nothing but play those games. I laughed, I cried, I was blown away, and luckily, I didn't get any blood clots in my legs.
Multiply that by about 2,000. My collection isn't just games. It is history. My history. The game's history. The industry's history. I can run my fingers down the spines of these games and be taken back to some memory - almost all of them fond.