i think we all can agree that there is no sure way to know exactly what caused the tire to fail. a TPMS is likely the only way to help prevent a full blowout, as it would would hopefully give low pressure warning ahead of full failure.
however, seeing my brand of tire on the very top of a list of "brands to avoid at all costs" makes me think it was at least partially due to the tire itself, or at the very minimum, avoid buying those tires as a replacement. i've read a lot about upgrading to LT tires, but I think I'd rather stick to tires specifically designed for trailers. but i will be getting a high load rating.
thanks for all the tips and advice!