Oh hey, its this topic again! I think I'll try to provide a different answer, just to keep things interesting.
I think that retro collecting will be a thing that 12 to 21 year olds get into in the near term future. It seems that, online at least, they have a good respect for this stuff. When I first discovered stuff like Gamefaqs back in the day, my degenerate 15 year old mind was opened to a whole load of video game things I hadn't known of before- and today's kids are just soaking in it. The internet is really kind to nostalgia and making people appreciate other people's childhoods. "Oh no, thats old", is something I never see people saying either online or off. When my younger family members are over its always more along the lines of "Wow, you have an N64!" As these kids get money, I think they will spend some on older games and retrons and such, provided they don't get priced out of the market. They're also lucky enough that, due to how long the seventh generation was, their "childhood" games are only one or two gens back and the super popular ones are still absurdly cheap. Of course I'd also say that the boom period is over in North America-prices seem to have visibly leveled off over the past half year. But that doesn't mean I think they'll be collapsing anytime soon- not on CIB games with any level of interest or rarity anyway.
However, thats a short term thing and the kids who come after them, though they might play retro games, probably won't give too much of a thought to owning physical media. Think of it as being like reel to reel films. Is it a good movie you'd want to see? Sure. Is it the way it was originally shown? Sure. Is the player right there next to it, also for sale at a reasonable price? Sure. And yet such things do not go for much in my experience. There's just little interest in the hassle and bother of such a set up when a download is so much easier. And thats only going to get more and more true as your 30 year old NES and games turn 40 and then 50, etc. Nintendium is a funny joke but these systems and games are going to start breaking one of these days, heck they already have, and thats going to frustrate a lot of people. Long term I see the retro fandom going more towards interest being dedicated to the games themselves and less to the hardware. Thats good for me, (I am a physical collector who's sick of the unnaturally high prices on common Nintendo titles,) but its good for the future players too- they'll have to put far less money up to buy into the hobby.
I also think that there's going to be, among game analyzers, a fine line between "classic" game design and "modern" game design. And thats going to be somewhere around the 5th/6th generation limit, with certain titles from both gens being on the "wrong" side, depending on how forward or backward thinking they were. Of course hindsight is 20/20 and PS2 linear shooters might join Mario 64 platforming in the dustbin of history, but I don't think they will. Thats relevant to this discussion too- old but "modern" games are going to offer less incentive to people looking for something they can't find in whatever the current release market looks like and might have lower prices because of it, despite being just as old as today's retro games are to us. Of course, conversely, the indie scene is pumping out loads of games that are just like 8/16 bit games but with fewer technical limitations. For all I know, the mere thought that these older games are out of date or in "dead genres" might be me showing how out of touch I am, compared to today's market.