Barbacoa is primarily beef cheek shredded usually with lengua its not the same as chopped brisket. By your description Its sounds like a reinvention which now makes more sense, why they won. No one has likely ever tasted it before.

Beef cheek is a cheap cut that people are now finding out about. It is the same as fajitas were in the late 80's and early 90's before they also got popular. My dad use to get a giant cow head and skirt steak for almost nothing then spend all weekend cooking. Unfortunately the same fate will eventually also happen to lengua and mollejas salteadas as well.