Vtable and vtable pointer is under the hood.

Yes, but any C++ programmer who expects to be hired will have a good understanding of vtables and vtable pointers. They are a lot less tricky to reason about than, say, thunks in Haskell.

What makes you so sure about that?

Those are trivial. And have little effect on performance. And are hardly used in good programs.

In practice they mainly displace function pointers.

They might destroy your cache lines though.