It defines what you consider a flop. If it is a flop by not outselling the combined sales of 3ds and Wii U, than your point is probably valid. It will outsell the Wii U, but Nintendo's biggest treath is whether people will spend $300 on a tablet without proper social functions just to play Nintendo games. Whilst if they get a samsung or another android player they will get a device that can enjoy them while travelling and has other functions besides gaming for the same price. Time will tell if this console appeals further than the hardcore Nintendo fanbase.
I am not a Nintendo fan (not even in the slightest) and I don't think their games are better than high profile game of other AAA developers. So for me the product isn't appealing. Whether the mass agrees with that will translate in the sales of the Switch. In that respect the Wii U has proven a dedicated Nintendo home console which is very Nintendo doesn't appeal anymore, but perhaps the handheld market is different since the 3DS is still a succes.
Please excuse my (probally) poor grammar
