No, this completely not about the presence or lack of a 'www'. I'm saying it's pointless to even ramble on about CNAMEs when the conditions necessary for this

No, this completely not about the presence or lack of a 'www'. I'm saying it's pointless to even ramble on about CNAMEs when the conditions necessary for this to /even work/ mean it would be just as easy to return an abstracted A record that points to the right/active resource in the first place... Like GTMs generally do /already/. When the query comes into the GTM for loadbalancedsite.com, the response isn't fixed--the GTM has already been keeping track of which nodes are up and/or potentially closest to the requestor and it simply hands back an A record with a reasonably short TTL without anyone having to pat themselves on the back for being 'clever'.