I highly doubt Skyrim will be the last Elder Scrolls game, unless Skyrim somehow manages to be a huge flop Bethesda will have no reason to think that it's not profitable to continue the series, and while it's true that in Skyrim it's revealed that the past games were all leading up to the events of Skyrim itself, this doesn't mean more games can't be made after Skyrim. Bethesda doesn't necessarily have to tie each game together, each Elder Scrolls game has been a standalone story. We've learned that each event was leading up to some future crisis, but that doesn't mean that they're all directly related, it's just that in the prophecy involved with Skyrim's story, the past events are signs that proceed the coming of Alduin. And I'm really not convinced that Betheada had this ongoing prophecy in mind all along, so just because this one prophecy is resolved doesn't mean therwe can't be new stories, the only thing that really needs to connect them to past games is the fact that they take place in the same setting, after Skyrim, Bethesda can start a new story that's not directly related to it. And Bethesda could still tie future games in with past games if they wanted to, after all, we weren't told about the prophecy of Alduin's return in Oblivion either, future games could be connected to Skyrim by information that we weren't told before them.
I suspect that Bethesda will continue making Elder Scrolls games until either Bethesda goes bankrupt (In which case, another company could still pick up the license later), or people stop wanting to play the series, neither of which seem likely in the near future, or the final reason that could happen is if Bethesda runs out of stories they could tell in the series, which I also don't think is close to happening, after all, we still have quite a few provinces we haven't seen since Arena, and all the provinces have potential to have different stories, it's not like after Alduin is defeated there's suddenly going to be no more threats Bethesda can use, and since each Elder Scrolls game has had a different protagonist, Bethesda doesn't need to choose between raising the stakes each game or having the hero lose all the items and abilities gained in the previous game, with or without explanation, to ensure that the antagonist of each game can be a credible threat, so Bethesda doesn't need to worry about not being able to think of a way to make a bigger threat than Alduin.
Lol..what? Where are you getting that? Why/how has every TES main plot led up to Alduin coming? That's just one prophecy completely unrelated to the other TES games.
I think the prophecy is what the poster meant in this case, as we've been told that past Elder Scrolls games were all signs that will proceed the return of Alduin, but like I said, I doubt Bethesda planned for that all along, and it certainly doesn't mean all new games need to be tied to the past one in some way.