Is this just gamestop though? I mean it's nowhere near the only place to buy a console (hell, it's not even the first place I think of). What about Amazon, Best Buy, Walmart, Target? Or is gamestop a pretty good indicator of how availability will be elsewhere?
They had millions of Wii U's ready at launch, didn't sell them, and had to buy them back from retailers and sell them as refurbs at steep discounts from their company store.
Maybe they did learn?
Well what they need to learn is how to gauge demand properly then. Yes, having too many is bad, but having too few will lose them sales. And with consoles you really need those initial sales to jump start your console (especially if you are starting to get in the downward spiral reputation of "no games" which if you don't like Nintendo games their consoles are definitely getting associated with).
If you don't get people when they are really excited to buy, at least a portion of those people will lose interest or find something else to buy with their money instead. Biggest rule of sales, get them while they are interested as people have short attention spans. It's why cars have packages rather than just letting you buy everything a la carte. Too many options and people go home to think about what they want and decide they don't need it (having packages for the options gives them fewer options while still giving them some choice so it makes it easier for them to choose). Similar thing here, can't get the console, you give them time to realize they don't need it or can get other stuff or simply just don't want to wait.
Take me for example. I'm somewhat interested in the switch. I got some bonus money from work I was going to maybe put into a 3ds and some one convinced me why not wait for the Switch? Thing is, I'm also interested in VR. Most likely I'll wait for VR (Fallout VR to be specific cause I wanted at least one game I'd buy VR for before I put my money into it and that was it) and put my money there but they could get me in all the excitement to get a Switch (patience is not a virtue of mine
). I can't find one... well, that makes it easier for me to save my money for VR. So that would be a sale they could have maybe made that they would definitely lose if I couldn't get one right away (cause once I put the money into getting VR I'm not going to be in the mood to spend more).