Well, since the Enclave are low on troops, do you think that would drive them into recruiting from the wasteland? They're leaders are gone, so somebody else would have to rise up. Maybe they would come to that decision?
Their goals and policies during the time of FO3 are in question and flexible... Eden is a hard-core traditional Enclave member, maybe because he is programmed to be on some level, but Colonel Autumn thought killing everything mutated was overboard, and during the final confrontation he seems to have the goal of activating the purifier normally, distributing pure water and actually helping the wasteland, in return getting the people's trust and obidience to the Enclave, which they would probably use to grow their forces. In other words, Autumn wanted power and control, rather than genocidal purity.
I would guess after the desctruction of the oil rig and such in FO2, the Enclave ended up consisting of seperated groups with possible differeny goals. Eden and Autumn took control over a large group of them, but probably not all, and all these groups and leaders might change Enclave goals and policies in some way... I would expect this to factor into future games on some level.