> There isn't anything about garbage collection that enables something that couldn't be done before. ...

True, there's always another way. But you can say same about almost any subject. In my experience about lock-free (and wait-free) programming, safe and high performance deallocation of the objects is often a problem. (Especially in kernel mode when context switching is not an option.)

Whenever high performance is required and it's possible to avoid atomics (CAS, FAA, LL/SC, etc.), (false) cache line sharing or even memory operations altogether, I'll take it. Not to mention CAS (or equivalent) loops and mutexes...