I guess it depends on the servers. I'm in academic/research computing and single-user systems are the anomaly. Part of it is having access to beefier systems for smaller slices of time, but most of it is being able to share data and collaboration between users.
If you're only used to cloud VMs that are setup for a single user or service, I guess your views would be different.
This is overwhelmingly the view for business and personal users. Settings like what you described are very rare nowadays.
No corporate IT department is timesharing users on a mainframe. It's just baremetal laptops or VMs on Windows with networked mountpoints.
Where i work, we have a lot of physical machines. The IT staff own the root account, and development teams get some sort of normal user accounts, with highly restricted sudo.