It is a generational thing. Everything comes back in style, eventually. Just look at the resurgence of LP's or 1980's vintage shoes such as Nike or whatever. People love that stuff for whatever reason even years after it is long gone from stores - sometimes enough demand is made to warrant re-issues of classic stuff (like LP's or new product in the style of the old).

Video games will be no different. The problem with video games is there is a HUGE after market reselling niche that are willing to overbid just about anything so they can feature it on their "channel" on Youtube. There is a bubble that is about to burst here and that group is probably the most to blame for it.

Stores selling just retro video games are probably going to die off quicker than we expect. I figure what will happen is all "retro" stuff ends up in little shops, not just games. Like a mega retro store where you can buy those missing NES games alongside the action figures that were released, or the game was based on, and a copy of the television series on DVD/VHS and the comics - all in one stop. That is what I think will happen to retro stores.