Just to add what AverageDutchGuy wrote, veterans (old‑timer cars) usually also have some other limitations imposed on them in most EU countries – like legally only able to drive them to meets and stuff like races, strictly recreational use and no daily driver, et cetera.Those can't possibly be road legal under current emissions and safety standards?
Friends have a museum with over a hundred old‑timers and young‑timers, although their main attraction and specialty is renovating steam engines – locomotives, locomobiles and stationary engines. Obviously almost none of their cars are on licence plates, as they'd feel it a heresy to take some priceless museum pieces on the road.