Tbh I’ve found that whenever I’ve hit MAX RAM, failed allocations are not the biggest problem you should be focusing at that time.

Sure, it would be nice to get an error, but usually the biggest threat to your system as a whole is the unapologetic OOM Killer

While this is 100% true for the system allocator, hitting OOM there you're likely hosed, it isn't true if you're using arenas. I work on games and being able to respond to OOM is important as in many places I'm allocating from arenas that it is very possible to exhaust under normal conditions.