The Enclave (East Coast/West Coast):United States of America.
Capital: Washington D.C.
Population: 20,000.
Everyone else would have died on the globe... Trees, animals, humans... The Enclave would be left alone with a massive stock of corpses lying around. They'd start slowly building cities and start the human progress again from the level of Stone Age, except that this time the human starts from America. Many would realize the damage they had done, and some would even go crazy. If they ever realized that thanks to them, the world will run out of oxygene and that they have no chances of rebuilding the world with such low manpower, the Enclave would survive but I don't think they would ever be able to leave the Capital Wasteland/California.
The Enclave (East Coast, Autumn's faction)Mutants are dead thanks to Enclave-Brotherhood cooperation. The latter was forced to give up soldiers and tech to the Enclave, which is by far the dominant political figure in the Wasteland. Colonel Augustus Autumn passed away some six decades ago, and now the Enclave is being run by Colonel Julius Winter. He has his iron grip over everyone else, and everyone else are his private property. The Enclave has begun repopulating the Wasteland, and have isolated themselves from the locals. The Enclave starts to spread around, eventually reaching Midwest and Canada, until it reaches it's limits and collapses due to failures in their system.
The Wasteland lives, mutants and ghouls are dead, but the human stock will remain in their oppressed and humiliated state.
Lyons' BrotherhoodMutants still run rampant. The war against the Enclave svcked so much power that the Brotherhood was severely weakened in quality and manpower. The wastes are in the same state as in 100 years ago. Just that there is no shortage of water now. Lyons is dead, his daughter too but her son is now ruling the Brotherhood. It has been reduced into a local army that recruits anyone interested and throws them into battles against Mutant pockets, Raiders, Talon Company and other nasties that roam the wastes.
Eventually, the Brotherhood will collapse due to the sheer impossible nature of it. The fractions of the once-proud Brotherhood start fighting each other for power. They all become aggressive Outcasts.
The PittThe system would have likely not changed. The system is too weak to expand yet too strong to collapse due to a foreign power let alone through own stupidity. The diseases spread by slaves and the rivers would likely spawn a deadly virus some day and would wipe out all the Pitt residents.