Well, it would be fair to call overcommit-less Linux stupid. There are a number of aspects of Linux that are only reasonable if you assume that memory overcommit is a thing, and would be radically stupid to include in an OS that does not overcommit by default. For example, fork(), which only makes sense with memory overcommit and shared copy-on-write pages. Process is using 50.1% of the physical memory? Guess it can’t spawn processes, since it has to fork() before it can exec() and there’s not enough memory to copy the process!

I’m sure there are other horrendously degraded modes that Linux can theoretically operate in (read-only file system?, unreliable system clock?), but disabling overcommit, while possible, turns Linux into an exceedingly crummy OS.