This is C++.

You should not pay the performance hit for features you don't need in a particular program.

In fact: It is reasonable for C++ programs to NOT use all language features.

I'm not disagreeing with you.

In most cases, not. Where there is a legitimate reason to share, share. Without, it is just sloppiness.

In the context of a game engine, I mean. You may be sharing a model or texture between multiple entities, and want to know when it’s no longer in use.

Even there, something higher up the stack probably knows too, and is in a better position to choose a good time to dispose of it.

Possibly! It really depends on how you've architected things. I said it's "reasonable" not that it's the one true way of implementing it.

I think we really are all in agreement here.