Judging how much launch stock to have is hard. On the opposite of the spectrum is the Xbox One. How many months, years did those things sit on the shop floor, people making thrones out of them. MS constantly trying to repackage the originals over and over again with game codes and cardboard selves. I think there are still Day One Editions in retail.
Nintendo does have a habit of having a short supply, but I don't think it was ever about marketing purposes as a primary or secondary reason, it is just simply having a short supply is a better problem to have than having too much. Having a short supply means every unit you make is sold and less time something is in retail, less cost it is to Nintendo from storage, management, advertising, kickbacks and excess factory capacity. If you want to make a change or push a new product, it is far easier to do if the channel flushes itself, even if you have to put the older item on discount or re-box it it will apply over a fewer number of units.
While I grew up with the NES, SNES and N64, I am in no rush to go back especially since I still have the hardware on hand. I still have a CRT in storage should I ever want the full experience. But I am likely not the people they are aiming for.
It is for all those people that over the years have sold, lost, damage or otherwise never had access or played these games in it's original state.
Nintendo is in a somewhat unique situation to do this as they do have enough games to package in such a machine even without third parties. This gives them the leverage to bring in the third party games on reasonable terms.
Imagine trying to do this with PS1 games where you would have to fight to get every single game you tried to get on the system. Don't forget the number of games that are now attached to defunct owners or have different version and re-releases, publishers, lapsed tech licenses etc. They could do it, but I can't imagine how much of a mess it would be.