i agree with most of this, I own a NES and every home console and handheld released since then and I pre ordered every nintendo console.
I loved every handheld they ever released, including small upgrades like the GBA SP and the new XL models on DS/3DS also I loved all their home consoles UNTIL the Wii.
They lost me with the Wii and Wii-U in the home console market and I would buy a handheld version of the switch that is smaller (its to big for my handheld preferences in its current state) and with a better battery life. And obviously, a much lower price.
I think anyone predicting the Switch will do well outside of Japan is being over-enthusiastic because they like the idea of the switch but its really really not a massive populair innovation like the Wii, its more like the 3ds where the device is "ok" but not everyone is on board and Nintendo will need to lower the price and make a ton of games to convince people.
If they will and can do this is ultimately not up to us but up to them and I think they can reach 50m sold on this console if they support it well but its not the return to form I and many others wanted in the Home console market.