That might depend on the number of plies.
I guess most people here were not born when bias ply tires were standard in North America and only sports car owners sought out radials. Radials were superior because of their better road-holding, precise steering, better fuel economy and they weren't squirrelly over streetcar tracks. Nowadays you mostly see bias ply tires on trailers. Since you can't feel a trailer tire going down right away like you can a tire on the vehicle you're driving, trailer tires take a lot of abuse. They need to be of much tougher construction, more plies. I have do doubt a radial tire made for trailer use would be superior, but it would cost a lot more. Bias trailer tires cost more than car tires as it is, so there wouldn't be much of a market for radial trailer tires.