I can't make categorical statements, either. But here's another concrete observation to offer as evidence that things are not so clear cut: in generational GC,

I can't make categorical statements, either. But here's another concrete observation to offer as evidence that things are not so clear cut: in generational GC, heap allocation is typically O(1). A heap allocation is typically O(n), where n is the size of the heap. Of course that difference also tends to go away if you're using static buffers.