I mean yes up to a point, but how do you even maintain such a thing? Like, if your garbage collector was written by a bunch of really smart guys who made sure t

I mean yes up to a point, but how do you even maintain such a thing? Like, if your garbage collector was written by a bunch of really smart guys who made sure that it would never allocate during collection by just knowing the internals of your system really well, sure that's great, but then how would you even know when you'd broken that property? And the failure mode isn't great (you presumably get a very occasional deadlock when you just happen to run down exactly the wrong codepath during GC). Most languages will let you bypass their layering if you want to. But it's usually ultimately a bad idea.