I can't think of any place on the globe that once been dominated by Islam has ever returned otherwise, especially back to Christianity with the possible exception of Cordoba in Roman Catholic Spain.
Colonialism? Syria and North-Africa where conquered by the French and Palestine and Egypt by the British. But don't let reality get in the way.
The reality is you are comparing secular nations as opposed to a religious, borderless, sharia-dominated state in Islam.
The reality is, once Islam takes foothold all worldviews including Christianity
are out and Muslims are in, end of story.
The French and British are long gone but Islam remains.
The reality is, there is no comparison.