I always envisioned the next big Pokemon game being either a MMORPG (very wanted, but extremely complicated to actually make), or a "Pokemon All-Stars", with every major region in the game, the ability to travel to/start at each, and progressivly higher level battles in every new region.
But actually complete the franchise? Naaah. #1, this last gen has already beaten the OGs as the fastest selling Pokemon game ever, *while there is still a DS shortage in Japan, so everyone who wants to buy right now can't, the number would be even higher*. #2, new Pokemon don't have to be more powerful than the old generations, just comparable #3, even though they now have North, South, East and West in the game geography covered, they've managed to pull entire regions like Fiore, Orre, the Sevii Islands, and other areas basically out of nowhere. It is *based* on the real-life Japanese geography, but they can alter it to suit their mood however they want. "Running out of good ideas" or "these new Pokemon are lame" are basically a personal opinion, and that difference of opinion obviously doesn't matter too much when the majority of Pokemon fans are scrambling for this game like never before, and new fans are being made every day. I'm always thought that there were a few lame ducks in every generation, even the first. But that's why we now have almost 500 different ones to choose from, variety is the spice of life.
I can't believe that you would actually think that a multi-million dollar franchise this sucessful would suddenly decide to "give it up". It doesn't make sense, it never WILL make sense, and it won't happen. Bad sales will kill the franchise, or an indirect/direct act of God, nothing else.