For sure, you can totally make something like this happen, but again that means writing and securing a bespoke system. If you’re a team managing your AWS infrastructure with Terraform, it sucks to have to write a totally different system (and all the secrets management that goes along with it).

Additionally, for a government agency you could have dozens of contractor teams, and you need a method of securing access for all of them. It’d be much easier to just use Route53 and delegated subdomains, as all teams are largely deployed and managing infra (with MFA) there.

But it’s not allowed, because DNSSEC.