Oh sure -- for piddly enterprise nonsense, having some VM yeeting magic to HA a thing that's not HA is .... yeah, I guess. Ideally in combination with tested backups for when the HA magic corrupts instead of protects, but such is life.
But that's not "at scale" that's just some great plains accounting app that's been dragged from one pickle jar to another.
In 2016 we had a 36k cluster. There was something like 2 PB of fast online storage, 48pb of nearline, and two massive tape libraries for backup/interchange.
The cluster was ephemeral, and could be reprovisioned automatically by netboot. However the DNS/DHCP + auth servers were on the critical pathway. So we dumped them on a VMware cluster to make sure that we could run them in as close to 100% as possible. Yes, they were replicated, but they were also running on separate HA clusters, with mirrored storage. This meant that if we lost both of them, we could within a few minutes run them directly from a snapshot, or if it was a catasrafuck reload the config from git.
Now we could have made our own DNS+dhcp server, and or kerberos/ldap/active directory. but that cost money and wasn't worth the time. Plus the risk of running your own with a small crew (less than 10 infra people) was way to high.
VMware was almost mainframe level of uptime, if you did it right.
But that's not "at scale" that's just some great plains accounting app that's been dragged from one pickle jar to another.