Well, I don't have any clue about sales to be quite honest, that's why I won't make any predictions. But a lot from the OP sounds reasonable. Also, people tend to underestimate Nintendo. I still remember how people said the Nintendo DS is gonna fail, it doesn't stand a chance against PSP, blah blah blah. We all know how that turned out. I also remember a lot of hype for the Vita. People freaked out when that thing was announced as NGP. It had them hardware specs for epic grfxx, it had dat 3rd party support, it was relatively cheap, it had everything people insist Nintendo needs for a successful console - and it failed miserably.
It's just too early for any kind of prediction. In the end, it all comes down to software. If you ask me, Switch sales will go through the roof as soon as Pokemon hits the console.
Official member of VGC's Nintendo family, approved by the one and only RolStoppable. I feel honored.