Except when it is. You'd be surprised what systems programming looks like. Reference counts are not re-used when memory is re-used. And again, even if for some

Except when it is. You'd be surprised what systems programming looks like. Reference counts are not re-used when memory is re-used. And again, even if for some reason you had a global 64bit counter that you incremented on every allocation and never decremented, and you could somehow handle a billion allocations per second, you'd have 585 years before that counter overflowed back to 0. No computer or program can run for that long.