Why can't I wrap a T* in an std::vector?

Question

I have a T* addressing a buffer with len elements of type T. I need this data in the form of an std::vector, for

Answer 1

The short answer is that a vector can't use your buffer because it wasn't designed that way.

It makes sense, too. If a vector doesn't allocate its own memory, how does it resize the buffer when more items are added? It allocates a new buffer, but what does it do with the old one? Same applies to moving - if the vector doesn't control its own buffer, how can it give control of this buffer to another instance?