Edited. I really shouldn't post threads before my morning coffee, I am a zombie before I partake of the bean.
At a lot of the places where this has been posted the excuse of "of course it did, it's a portable" has been bandied about a lot, but I feel this is an oversimplification. After all, Vita being portable didn't stop the PS4 outselling it in Japan.
Yes let's compare the system that did 15M versus 100M globally because of reasons.
Do you really think if Switch was a full blown console it would have sold at over double the speed?
One could argue that the Switch is treated like a console. Nintendo themselves advertised the Switch as a home console first. Heck, consumers are awaiting games like Fire Emblem, Animal Crossing, and Pokemon because they are getting the home console treatment (i.e., HD graphics, bigger scope/scale, etc.).
Plus, the pricing leans more towards home console than handheld. The big Nintendo games and most of the third party ports are priced at $60 and the Switch is priced at $300. The Wii sold like gangbusters at its launch price of $250. Granted both consoles are completely different in technological structure and power.