They never claimed the NES classic was a limited time product until they had pretty much discontinued it.
This time around they said the snes mini would only be sold through the end of the year, but that they would be doing their best to drastically increase production so everyone could get one.
The problem is that Nintendo is horrible at communication. So instead of saying something like "the mini nes/snes consoles were always meant to be limited quantity items and we cannot guarantee that everyone will be able to get one. However, we understand that our fans would like to play the games on these mini consoles even if they cannot secure one, so we will look in to releasing them as bundles on other systems."
or they could simply make more of them...