Does this hypothesis also discard Luther's rebellion against the western church, and all the national churches that emerged in its wake? And, what about all the American and other sects that have also emerged more recently?
Your question, Powermetal4ever, raises other more complex questions about authenticity. Why exclude the Syrian/Nestorian church - they had congregations all across Asia, including China,
And, what about my favourite post-Jesus sect/church, the Manicheans? The prophet Mani preached all across Asia too. in fact the last Manichean temple remianing in the world, can be found near Quanzhou in southern China, once likely the biggest international trade port in the world. Here's a pik of the temple as it is today,
and, this is an image of Mani (who some contemporary Chinese who worship at this temple conflate with the Buddha)?
If you you would like to know more about this temple, here's an article in a contemporary English language Chinese magazine called Radii.
Even in the first few centuries of what Christians imagine as the 'pure' church, arguments raged between rival groups.
What did Jesus teach? We cant really know for sure, The earliest writings (the gospel accounts) were written some 20 years after Jesus died. Can anyone recall exactly what someone said 20 years ago?