Sure, but that doesn't really help for user-facing services where people expect to either type a domain name in their browser or click on a search result, and end up on your website every time.
And the access controls of DNS services are often (but not always) not fine-grained enough to actually prevent someone from ignoring the procedure and changing every single subdomain at once.
And the access controls of DNS services are often (but not always) not fine-grained enough to actually prevent someone from ignoring the procedure and changing every single subdomain at once.