I used to collect RPGs just that way. Indeed to a very limited extent I still do in that I have several RPGs but don't play RPGs in person ever. I just read them and sigh. (And yes, one of them is Fate Core plus the system toolkit plus Fate Accelerated plus the Romance in the Air setting book…)
Basically whenever "money" and "personal obsession" cross paths in my life, I start collecting. It's pretty fucking bad, actually. There's a reason why my wife manages the money.