> special case where all memory can be easily handled in arenas That seems to be an unfair bar to set. If _most_ objects are easily allocated by an arena, then that still removes most of the need for GC.

I like Jai's thesis that there's four types of memory allocations, from most common to least common:

1. Extremely short lived. Can be allocated on the function stack.

2. Short lived + well-defined lifetime (per frame/request). Can be allocated in a memory arena.

3. Long lived + well-defined owner. Can be managed by a subsystem-specific pool.

4. Long lived + unclear owner. Needs a dynamic memory management approach.

If you want to make the claim that tracing GCs surpass manual memory management in general, you should compare to a system written with this in mind, not one that calls malloc/free all over the place. I guess it might be more fair if you compare tracing GC with modern c++/rust practices.

I agree that for most systems, it's probably much more _practical_ to rely on tracing GC, but that's a very different statement.