I don't mean to offend, Mike (especially a fellow MIKE!), but having spent my entire career in an industry that is rife with scientific innovation (albeit not for safety sake...usually for performance and satisfaction) I and any other readers here who've spent their lives in a competitive business environment, can tell you there's no way in hell that Dunlop, Bridgestone, Goodyear, Cooper, Michelin, Continental, Pirelli, Yokohama etc, etc, etc are gonna GIVE away all their hard earned (and very expensive) research just so that "Kookamunga" tire company can undercut them all by 60% at the cash register.
Also, who would "write" the law? The US? China? Britain? Japan? Sweden?
If your tire guy wants to sell some off-brand tires that ONLY HE has a distribution rights to in his city, county, state....let him cook up a story for you about the engineering prowess of his supplier, but the story he settled on is totally implausible, for a number of reasons.
Ask him for the name and source of the law.

Also, to test another source, I plugged the question into perplexity.ai, my new genius source for answers to questions on EVERYTHING.
It says: "Based on the search results provided and my knowledge, it is not true that tire technology related to safety has to be made public for all manufacturers to use. Here's a breakdown of the key points:

Proprietary Innovations

Tire manufacturers often develop safety innovations independently as a competitive advantage:

• Companies like Bridgestone, Goodyear, Michelin, and others have introduced proprietary technologies such as run-flat tires, self-sealing tires, and airless tire concepts
• These innovations are typically patented and not freely shared with competitors.