It makes sense to regulate what can be sold new, while grandfathering in what was sold legally in the past. People won’t stand for the government jerking people around and saying “this vehicle you purchased legally is now illegal and can’t be driven or sold, and you need to buy another with your own money… but no guarantees we won’t immediately ban the new one also.” Cars have a finite life span unless restored at great expense, so the problem takes care of itself without overbearing laws that would be seen as the government stealing peoples personal property. Appreciating classic cars is also a mainstay of American culture- with most towns having classic car shows, and things like discounted registration and insurance for antique cars.
From the way I read the article, it appears to me that the vehicle registration must be renewed:
>But Massachusetts is now pointing out that kei trucks and vans don’t meet federal safety standards and recently included them on a list of vehicles that can’t be registered in the state. The state is now reconsidering that decision, leaving kei truck owners wondering whether they’ll be able to keep driving these vehicles.
>All existing unexpired registrations for Kei trucks and vans will remain active as the RMV works to review and assess industry standards related to Kei mini trucks and develop an updated policy addressing the registration of these vehicles. From: https://www.mass.gov/info-details/vehicles-that-cannot-be-re....
So depending on how registrations in MA work and if they expire, they will be pulling the rug out from under the owners.
Related, if we are worried about crash safety(ostentatiously of the operator and passengers) why does MA still allow motorcycles?