I don't understand how you can come to the understanding that "heterodox" isn't a term of art when there's an entire wikipedia page devoted to explaining the me

I don't understand how you can come to the understanding that "heterodox" isn't a term of art when there's an entire wikipedia page devoted to explaining the meaning of "heterodox" (and another one about "mainstream") in the context of economics... An economic theory described as part of "heterodox economics" can, in fact, be relatively mainstream given enough exposure and enough followers (which is where MMT is today). Conversely, parts of "mainstream economics" are relatively controversial and are thus heterodox ways of thinking. If you think about "orthodox Christianity," the word "orthodox" says nothing about its popularity. The same goes for "heterodox economics." Pretty much all monetary theories are parts of heterodox economics.