I once spoke with a technical person at Bay State Milling, the miller of the Bouncer high-gluten flour and reportedly also a miller for King Arthur. He attributed KA's success to a combination of having first-rate flours but also first-rate marketing. He talked more about their marketing than their flours.
I would guess that the All Trumps high-gluten flour from General Mills is one of the most popular among pizza operators who want high-protein and high gluten. However, many operators, especially those who deliver, are as likely to use lower protein flours, such as a bread flour or a blend. Crusts made from those flours are less likely to turn hard and chewy by the time they reach their destination. Many operators, especially those with great ovens, can even get away with using all-purpose flour and turn out some very decent pizzas. That has been one of the greatest revelations to me.
Unlike fancy bottled waters, it is harder to use flour types for marketing purposes, and this is even truer at the pizza operator level. Instead, pizza operators will proclaim that their doughs and sauces are trade secrets (joking that "if I tell you I will have to kill you") or that the water they use in their doughs is the reason for their great pizzas. Or they build themes (some might call them gimmicks) around their pizza to attract patrons. The truth of the matter is that there aren't as many differences between their doughs as they would like us to believe. The dough formulations are usually fairly standard formulations developed with costs and profits in mind more so than quality. That's one of the reasons why there are only a few artisanal pizza operators around. For them, quality is usually the differentiating factor for marketing purposes, and cognitive dissonance is more likely to be at play there as they try to convince patrons to pay up for what they get--by differentiating what they do (e.g., using imported Italian flours, tomatoes and olive oils, wood-burning ovens in full view of patrons, serving pizzas uncut, etc.) from what the rest of the crowd dishes out. This raises the bar for what they do because the quality has to be there consistently.
P.S., bigriver, Balancer is a Pillsbury flour.