Ok, let think, that civilized humans, in Vault-City, NCR, BS or Enclve has armor for many generations to future. But... But why farmers, traders, raiders, tribes, CAESAR'SLEGION, at end, dont use it? Morrowind's ashlanders or Skyrim's Falmeri look more intelligent, using nature armor, but in the wastelanders never even try to do for example, mirelurk cuirass!
So, subject is a question.