why would it be stupid? this isn’t ‘implied’; that’s literally the story. ignoring that the Fallout TV show is really just an incoherent misanthropic screed which is an extension of Todd’s contempt for New Vegas, Obsidian and Interplay:
the resource wars weren’t going to end any time soon, the USian people were getting tired and socialist sympathies were rising. it was established in New Vegas that the US false-flagged themselves in order to justify a nuclear exchange against China in order to cull the population and reënact Manifest Destiny. part of the Enclave’s whole deal is trying to genocide the wastelanders to prepare North America for recolonisation.
it’s been my headcanon as far back as Interplay’s Fallout that an Americanist cabal believed the USian people were the US’s true enemy, and that by false-flagging themselves they could force a chosen few into the vaults where they could experiment eugenically with creating the ideal society to inherit the post-apocalyptic world free of foreign adversaries.
VaultTec’s product is the end of the world, so they sold the end of the world.
more or less
they underestimated how much life would survive on the surface; they couldn’t have predicted the Forced Evolutionary Virus; the Enclave (US rump state) is too fractured and horrifically incompetent to reënact Manifest Destiny; and most of the vault experiments failed catastrophically (if they weren’t cut short by mechanical failures, deliberately or not).