I'm kind of reminded of the speculator boom in Comic Books here. As people like Linkara have pointed out, the reason really old comics are rare and valuable was because not many copies are floating around anymore. You can't artificially create a valuable comic just by declaring it a limited collector's item... inevitably people are going to buy several copies anticipating it becoming valuable, and then it doesn't... because collectors bought dozens of copies so its nowhere near rare or expensive.
In effect, what the post two posts above me said people are doing with modern games. Stuff from older generations, nobody was seriously collecting and a lot of it wound up disposed of by kids who didn't know better, that's why its rare now, but as adults we expect a niche RPG or whatever to become collectable in 30 years.
There's also what another person said, how so many releases are digital now.
Honestly the only games I think will truly become rare are gonna be weird situations like say Silent Hill P.T. or any other case where downloads/updated versions are impossible to get. I mean, unless everyone just embraces piracy.
Games released as limited collector's items seem to rise in value about as often as games in general do. A few do, most don't. I've been selling off some of my older PS4 releases from LRG, and a handful have increased to multiple times what I paid for them. But there are far more that I'm more or less breaking even on. But that's the nice thing about limited releases. Even if they don't increase in price, they don't tend to drop in price much either. I don't know if we'll ever see a LRG release worth less than 5 bucks like a copy of Madden or some such. So in that way, limited releases are kind of "safe" investments. That said, video games have never been worthwhile as investments.
I'm gonna start buying up copies of Madden 2016 until no one can find them anymore, then I will slowly sell them off, charging 100x what I paid for them initially 😁