I think its strange they didnt make a bigger deal about that guy finding the cure for the FEV mutation, i think its something really big in the Fallout universe. Perhaps something more about it will come in some DLC?

It was only the sure to the strain the institute infected upon the populace.

It even says in the Prydwen that the super mutants are of an entirely different variety here, then they were in the capital wasteland.

More then that, the cure Virgil uses is keyed to his genetic structure alone, it won't work for any other Super Mutant.

Plus, that assumes they're even curable. Virgil was able to maintain his intellect through the process - the vast majority of Mutants do not.