You're wrong. We only know that the universe without Fry, the Professor, and Bender goes on. (And even then, the universe could be considerably worse without them - when Fry "saves the universe" from the brains the first time, it's just from being enslaved by them, but the universe would still go on). Anyway, the universe with Fry, the Professor, and Bender goes forward differently BECAUSE of them. Fry may need to save save the universe as a result of their own actions, directly or no.
Why did I type this