Every region's launch day was different, but if you combine them together, the Wii U actually sold a little over million units on launch (400k in North America, 40k in the UK and 600k in Japan -- I don't have official numbers for the rest of the PAL region).
Compare this to the PS4, which sold...
I'm not 100% on board yet, but the Switch definitely has my attention. I dig the control scheme and that it's also portable (which is a huge plus for me -- I'm constantly on the move so handheld tends to be my preferred method of gaming), but there's still a lot of questions I need answered like...