Originally Posted by Couchpotato 
They will in the new trilogy coming out didn't you hear. There already working on the next installment as confirmed when the docs left. I don't know who will be the next lead.
They would be fools to stop the franchise.
Most likely it will be a prequel (first contact war? Which I have no interest in, personally). Not sure how the could do a new game post-reaper invasion, given the very different ways you can end ME3.