Is priming with sugar or DME for carbonation practiced in industrial bulk beer production or is it a carbonated technique that is used solely for bottle conditioned beers?
Depends what your definition of industrial bulk beer is. There are some smaller breweries that naturally condition kegs and casks, although finding them isn't that easy. I searched "breweries that naturally condition kegs" and found a few and also many stories about the practice.
There’s krausening, for those who are Reinheitsgebot-impaired. That’s when the sugar you add is in the form of actively fermenting beer. But arguably the same thing!