Your second half contradicts the first half. Those retro systems like NES Mini are new products that people don't mind rebuying when they feel nostalgic for old games because they come with a bundle of games in a neat, convenient package. No one wants to dig out old cartridges and discs in dubious condition and struggle to get them working on modern hardware. You have hundreds of old games you'd want to play that you'll likely not get around to most of them since new games come out everyday, and even many of your old ones will be remastered or repackaged to work better on modern systems.
I don't see the contradiction at all. The entire post was saying that people don't stop caring about games because they're old. Now, I can only speak for myself on this part, but I have an entire shelf full of PS3 and PS4 games (and boxes of PS2 games in my closet.) I spent good money on them, and they are all in pristine condition, and I would like to be able to play them. Unfortunately, I can't play my PS2 games due to the fact that my launch PS3 with BC dying last year, and hooking up my composite PS2 to an HDMI 4k TV is pretty much impossible, but if I could pop a PS2 game into a PS5 and play them with upres'd graphics, there are whole lot I own that I would like to be able to play. And we're talking about a console here, not a PC, there shouldn't be any struggle to get them to work on modern hardware (either they do, or they don't.)
Now, I will admit that I do tend to play more current gen titles than previous gen titles, because like you said, there are new ones coming out every day. This causes the older ones to fall by the wayside, of course. But if you haven't played them yet, they're new to you, even if they were bought a decade or so ago.