Honestly, I think a lot of this stuff is silly. I mean, they could easily put a lot of those games on the Wii, Wii U or Switch, and they have already, take Super Mario All-Stars (Wii), for instance. However, though, people want the original system for nostalgia purposes and I can't blame them somewhat.
Anyway, another advantage is the fact the system is way more kid friendly, but that's probably not the major motivation of the buyers.
With UK stores not taking pre-orders anymore, it is obvious there's unfilled demand out there. I'm surprised that Nintendo don't produce a load more of the consoles. They could make more money and flood the scalpers out of the market.
I won't be buying one, though. As a die-hard retro gamer I have the original.