Once Saudi oil runs out, I don't see why there shouldn't be mass secularisation and the emergence of less hardcore versions of Islam. Societies might even become far more tolerant.
If they were poor today, and just discovered oil, your statement would have been:
"Once Saudi start selling oil and get rich, and educated, and their lives become better, I don't see why there shouldn't be mass secularisation and the emergence of less hardcore versions of Islam. Societies might even become far more tolerant. "