While, if you walk into various pizzerias in the NY area, you'll probably find a few more Baker's Pride ovens than other brands, I wouldn't consider them to be the 'vast majority.' There's plenty of Blodgetts, Bari's and Marsals, as well as other lesser known brands. Perhaps if you go back far enough, to perhaps the 60s or 70s, BP might have put out something superior to Blodgett, but, as far as the last 30 years goes, you find just as many old Blodgetts hanging around as BPs (or other brands).
As far as I'm concerned, whether or not you're buying an old oven or a brand new one, brand is not really that critical. What is critical, is the specifications. Years back, quite a few ovens could do fast bakes, but, now, that number is two- at least on the gas side. Things like BTUs, watts, peak thermostat temp, stone thickness and material, oven chamber height and brick lining are far more important than brand.