At one point Buddhism was one of the worlds largest religions and places like Bukhara, Afghanistan, Pakistan, Bangladesh, India, and Sri Lanka were all Buddhist majority.
Then they got wiped out by Hindus and no one practices Buddhism anymore in those countries.
The Levant had heavy Byzantine influence and was very Christian, that place is Muslim today.
Iran was a Zoroastrian powerhouse and now no one practices that religion in Iran today.
You can achieve anything as long as you have a will and a plan to do it .