I'm not sure VM/370 is less suffering. For example, I run MVS in the typical old 3.8j version (the last public domain one, from I think 1981) as an enthusiast, and it's just amazing how little abstraction there was. MS-DOS practically cuddles you, having an actual file system!
it's just amazing how little abstraction there was
That was deliberate and made a lot of sense. The functionality was split between two programs. The VM/370 part emulates the raw machine. CMS is the "operating system" on top of the VM "hardware".