Why doesn’t the C++ default destructor destroy my objects?

What makes you think the object n points to should be deleted by default? The default destructor destroys the pointer, not what it’s pointing to.

Edit: I’ll see if I can make this a little more clear.

If you had a local pointer, and it went out of scope, would you expect the object it points to to be destroyed?

{
    Thing* t = new Thing;

    // do some stuff here

    // no "delete t;"
}

The t pointer is cleaned up, but the Thing it points to is not. This is a leak. Essentially the same thing is happening in your class.