The Guitar Hero & Rock Band games seem to have peaked. No more versions may be produced. Eventually, the controllers will be discontinued. New consoles will come and the old ones—along with their controllers—will get sold in garage sales, given away, etc. The controllers will also start breaking down. Thirty years from now, it may be very expensive to get a working console and working controllers to play some Rock Band with friends.
There’s a great Avalon Hill game called Magic Realm. If you’ve never played it, it will cost you a lot to get a used copy. It has so many parts, there’s a good chance a used copy will be missing some.
Thirty years after the classic, c. 1981, D&D Basic and Expert sets were published, you can download a copy of Labyrinth Lord or Basic Fantasy for free and play pretty much the same game. In another thirty years, that should still be true. (Heck, I’ve got the rules on my phone.) Sure, you need a computer, a connection to the Internet, and—optionally—a printer; but the expense of those things are spread over lots of other uses. If polyhedral dice become hard to find, you can fall back on electronic dice simulations. (I’ve got a bunch of such apps...on my phone.)