More than 30 years ago, I used to do a golf trip to Myrtle Beach with 11 other buddies. One of the guys was a highway engineer. He told me back then that many interstates were never designed to support the weights and amounts of semis using the interstates. No doubt that without the semis, the interstates would last forever, but we'd all be growing our own veggies and slaughtering our own cows and hogs for meat.
And you can't permanently fix the problem by adding another layer on top. The road beds need to be deeper, and its too late for that. So we patch. And cuss.