When I see a statement like this I am curious as to how it was arrived at.

Would many years of living in various places in China, with several gigs as a hiring manager for foreign teachers, AND nearly 8 years of running a forum for China-based expat teachers make any impression at all?

Obviously, there's no "nationwide poll" on such matters; we have to rely on personal observation. I like to think my personal observation has cast a pretty wide net...and it has come up with relatively few teachers who didn't have some kind of degree.