I think a lot of the problem stems from the specs the camper manufacturers use, not the tires themselves.
Case in point - camper in my sig is 7300# loaded. It came from factory with a gvwr of 10,000#. Has 5300# axles, and D rated tires. A well speced trailer, IMO.
I've seen newer rigs, longer, with a 10,000# gvwr. Weigh just shy of 10000# loaded. Came from factory with 4300# axles, and D rated tires. Which safety margin would you want?
Until manufactures start specing axles/tires with a significant safety margin, vs the bare minimum of what will work - we are going to continually run in to these issues.