Call me a tin foil hat conspiracy theorist if you must, but I think Nintendo intentionally made too few because they didn't want people to buy them. Instead, I think the whole thing was a viral marketing ploy for their Switch. They don't make enough but remind the gaming public how much they like (liked) Nintendo.
The "They don't make enough" part is so that the casual consumer won't buy a single NES with 30 games and then call it a day for their gaming budget for the next year or whatever but instead are essentially forced into buying a Switch if they want to get some of that sweet Nintendo gaming.
I seriously don't like Nintendo as a company anymore. Yeah, some of their games are still games that I want to play but I hate the idea of me giving them my money. I haven't felt satisfied with a Nintendo system since the SNES. Now this happens; I don't even want the stupid thing for myself as I'm good on NES games. I couldn't get one as a Christmas present and I'm still trying to get one now. I've waited in lines, I've tried to buy online, I've used brickseek online to try to get one and I still have nothing to show for it. The one time I saw one just sitting in a store for sale it was marked up to over double the MSRP. Way to drop the ball on consumers, Nintendo.