You're probably right and honestly, I'm fine with that. 3rd party games don't sell well on Nintendo hardware and Nintendo seems to be fine with that, too. They don't seem to be chasing after 3rd party support, but what they do get works great on Wii U (Rayman Legends, ZombiU, etc). I don't look for Madden or Call of Duty or FIFA on Wii U and nobody else does, either.
They need to just release a universally accepted console with architecture that everybody can relate to (i.e. normal controller), make it powerful enough to run their 1st party games in HD, market it well from launch so everyone knows what the hell it is, have a killer (and I mean, KILLER) launch lineup, and choose a price point that will be accessible to the general public and low enough to turn a profit on a smaller install base. At this point, Nintendo selling 20 to 30 million consoles is a success to me, as long as they turn a profit and have enough games to satisfy me.
Nintendo still has some of the strongest 1st party IP in the industry and they make incredible games. Just make a console that everybody can afford and play with ease. Give us the franchises we know and love: a gorgeous 3D Mario game, Zelda, Metroid, Fire Emblem, Kid Icarus, Starfox, F-Zero and all those, sprinkle in a few new IP (i.e. Splatoon) and then, sit back and watch the money and 90+ Metacritic scores roll in. They won't have the 3rd party games, but they'll have gamers' respect and enough money to keep doing their thing.
TL;DR: Yeah, 3rd party support probably won't return like the glory days, but that's ok as long as Nintendo keeps making money and releasing their awesome games.