if trailer tires only good to 65mph, why not switch?

I think the OP's question goes to the issue of why ST tires seems to fly apart. It does not have to do with mpg or any of those issues. The fact is I can load down my truck--way over weight--with a load of wood until the back drags the ground and the tires don't fly apart. I can go 70 or 80 or 100 mph and tires don't separate. Forget all the issues around why we should drive slower, why can't we have a ST tire that withstands the abuse our car and truck tires go through every day?