Was anyone else hoping Nintendo had finally caved on this angle?
No... not really.
Pokemon has always been a very simple game at heart and a MMO would kinda be... exactly like pokemon with nothing to distinguish it from the games.
Which is exactly why they havn't made an MMO, among others, is that really... why make one? They are limiting themselves both creatively as they will forever be strapped to their MMO engine, and they are limiting themselves monetarily as selling additional pokemon games become more complicated.
It is why Pokemons with strong internet focus have always been kinda outright battle engines with nothing else really being there.
If they made a Pokemon MMO they would have to make it... different then the game.
Heck I heard a mock version of a Pokemon MMORPG made as a joke and it didn't even sound possible as it relied on having more flexibility and structure then any pokemon game has ever before.
Of course it would have to be different O.o Just like WoW was different from Warcraft, just like STO was different from any other star trek game (which is almost entirely good). You don't have to stop making single player games, there's always going to be that niche. But they've already made non-gameboy pokemon games that were great, like Pokemon Snap, the TCG... ok, well that's all I can think of really, as Stadium was like you said, a battle simulator.
Point is, it's not like it's impossible or that there aren't ideas that could work, Nintendo has just been very slow to take advantage of online gaming, never mind any sort of platform besides their own systems. Just think about actually having to chase down and provoke wild pokemon in their natural habitats in order to catch them, and running into and shanking other trainers who have the same idea. Then finding out that the pokemon you
subjugatedtrained has a family of baby pokemon, which you've just made prey to the roving bands of wild miltank and diglets (it's a grass-type) Now trade it away to some shady trainer with the same pokemon of the same level to bury your shame forever. See? Ideas!