I think that Nintendo has pushed advertising on 3rd party games, the ones that mattered. However, as others have mentioned, it isn't Nintendo's responsibility to blow their advertising budget pushing games that aren't their own...unless those games really cast a spotlight on Nintendo's image.
The main problem with AAA 3rd party games, is that they are often either: late releases or ports, ports and late, ports, late and higher price while other versions are on discount....or ports, late, higher price and half the game on too small a cartridge.
I don't see how Switch could sell that many more units by Nintendo pushing 3rd party. Nintendo's own games are whats pushing sales. Especially for people that are on the casual blue ocean side, which is a larger market to reach than the gaming crowd...which already know about the 3rd party games available and are happy to purchase those games on the other systems available, due to the above mentioned factors.
