Oh, I've been up down and all 'round with all aspects of trailer tires....it was a poke at ST humor. :grinn
Never understood the Sidewall flex myth though; they all drag in a turn, they all have scrub wear, doesn't matter what's on the wheel for a tire. It's the nature of the beast with multiple rigid axles. You should see the flex on heavily loaded triples.
Knowledge in backing/pull-ups can limit the sidewall loading, but it's still detrimental to both LT or ST tires.
Abuse History. Every tight turn with heavy twisting sidewall loads, every curb you flex it over in either backing or leaving, every pothole you dodge with the truck but the trailer tires catch, it all adds up in weakening the tire and....pop! Or if you inspect regularly and often when in use, you catch the bloated sidewall, tread separations and/or bloated centers, before they blow out.
In carrying a heat gun along and monitoring sidewall temps when underway, what I have noticed is that the ST tires run Significantly Hotter sidewall temps than like LTs, whether on the truck or in use on the trailer, empty or loaded.
Excessive heat is what causes any tire to separate and blow. Higher speeds, too low of psi, too hot of road conditions, punctures,....so many factors, it's always a guessing game as to fault. I think it all factors in with abuse history of the tire. I think that's where the LT excels, with stronger sidewall construction to hold up to the abuse and run at lower temps as a result.
10 LTs and 4 STs in trailer use (down from 16 STs)...I've never had an LT failure and actual punctures I can count on 1-hand after years of service. Actual, for many times I can just pull the nail/screw/metal out and it never punctures the inner carcass.
Complete opposite history with ST use, where I was at a Discount 1-2 times a week for either a flat or replacement. I knew all the local Mgrs by 1st name. Downerrr
After the switch, it was 4 months before a visit, and it wasn't an actual puncture...1-5/8" roofing nail dead center, no leak.