a pyramid is not a pyramid when it doesn't fulfill the requirements of a pyramid.
Here is the answer!
When is a "Pyramid" not a pyramid? Never!!! How can something that "IS" not be "What it is"?
they will always be known as pyramids even if their shapes changes a bit.
Take the Temple of Artemis as an example; nothing remains but a column, but people still remember it as one of the Seven Ancient Wonders of the World.