Honestly, I don't think the average nostalgic Gen X-er is that interested in a sealed video game cartridge.

I think the "sealed, unopened, graded" flavor of collecting is always more of a niche thing, and the actual market potential of tapping into American Gen X video game nostalgia is more clear when you look at sales of the NES/SNES Mini plug and play consoles or the Nintendo Switch subscription for classic games.

Collecting is an absolute rabbit hole, and it's often intrinsically tied to the "lore" and history of the collection's theme/genre more so than a collector's personal feelings of nostalgia.