Just for the record, even in Italy the winter tires are required for the season (but we can just have chains on board and we are good).

Double checking and it doesn’t seem like it? Then again I don’t live in Italy. Here in Sweden you’ll face a fine of ~2000kr (roughly 200€) per tire on your vehicle that is out of spec.

https://www.europe-consommateurs.eu/en/travelling-motor-vehicles/motor-vehicles/winter-tyres-in-europe.html

Granted that you need to write a more complex law, but in the end it is nothing impossible.

…and thus it is much simpler to handle these kinds of regulations at a lower level. No need for everyone everywhere to agree, people can have rules that work for them where they live, folks are happier and don’t have to struggle against a system run by bureaucrats so far away they have no idea what reality on the ground is (and they can’t, it’s impossible to account for every scenario centrally). Even on a municipal level certain regulations differ, and that’s completely ok!