If it were true it would be odd. However, for some strange reason you believe a myth.
That's because the vast majority are mainline Protestants
Wrong again. Only a small majority are mainline.
Nonsense.
There are about 2.1 billion Christians in the world and of those about 1.4 billion are Catholic and Orthodox.
Of the remainder:
105 million are Baptists
75 million are Methodists
87 million are Lutherans
75 million are Reformed/Calvinist 82 million are Anglican