On the other hand, FOX are eager to get a "Simpsons" movie out to fill the coffers, and they can't (and the team won't) do that while the series is still in production. So it kind of balances out.
The FOX that makes, produces, and runs films is different than the one that runs the FOX TV station. FOX is fully aware that taking out The Simpsons would hurt it more than the money the movie will make. They'll continue to milk the seasons until there is a great decrease in ratings therefore making it a better finacial move to produce a film.