I'm just repeating what Anthony said the actors were told when they signed up. If it had been a HUGE HIT who knows what would have happened.
This is the first I've ever heard of Enterprise movies being talked about while the show was in production still. Even though I liked Enterprise, even I have trouble believing there were definite plans for Enterprise movies. That could have just been smoke blown up someone's butt to get them to sign a contract or something. Obviously, even if that were said and it was meant, with Nemesis floundering and Enterprise ratings never living up to expectations, those big screen movies never happened.
Now, I do see some sort of logic to that idea, as even before Nemesis was released, it was billed as a "Generation's final journey" or something similar, and with TOS, DS9, and VOY all resolved, that left only ENT as the last Trek franchise up for movies after TNG went away, at least without either rebooting or creating a new show\movie series (which of course we got).
Also, it could explain why Enterprise seasons 1-3 seemed to be held back at times...maybe they were hoping to do an "xfiles" and release a theatrical movie in between seasons or something. Just speculation on my part, though.
So I can see how maybe there was "TALK" of doing Enterprise movies, but I would be surprised if it was anything other than that.
But all that said, I still lament to this day we never saw an Earth-Romulan war or conflict ( I know I have said that a lot.... sorry). Had Enterprise stayed on the same track as it was in seasons 3-4 , I think it could have been a pretty awesome season 5.