IMO, do not rely on a website that amounts to information that is nothing more than someone's ungraded term paper. All but one reference is several hands-removed from fact. The Carlisle reference is the only one worth any weighting and theirs is actually a pretty good one that has hung out their qualifiers for public knowledge the longest (but they also had the toughest run with bad STs). Anyway, seek out conversations with the technical folks (definitely not sales folks) and review the product literature from the manufacturers directly for yourself.
Specifically in your highlight, the first two sentences are true outside of EU-code tires. The third sentence is not fact, it's a derived opinion and you will not find it in any ST-tire manufacturers technical summaries, specs, or sales sheets. This is because it's not that simple. It's a more complex interaction of the tire construction (more shoulder than sidewall), compound, profile, and tread that equate to cornering behavior. Further, cornering behavior is not the same stress condition as a turntable maneuver that I was specifically discussing, which is actually a design consideration to a steer tire.
That said, ST tires actually have not changed substantially since their introduction in terms of structure. Certainly some tread variation. The materials definitely have changed in terms of rubber compound and also the belting (sometimes for the better, sometimes not), but not really any fundamental departure from the traditional North American ST design approach. As far as the tire manufacturers see it, there's no demand and R&D is pennies in a bucket compared to passenger vehicle tires.
In these years, I am only familiar with some numbers from one major source of ST tires for a 5 year snapshot. The number of reported failures and complaints barely register a full percentage point versus number of collective units sold. Barely 1%! No doubt in my mind reporting is a gross underestimate because the end-users don't report the failures. One way or the other, they deal with it and move on or assume they did something wrong - how can't you when you read the stipulations of the ST warranties and all the conditions in the guides put out by Carlisle and the others, and I believe now all ST tire makers cut off life at 5 years in writing. It is actually a reason why you can often get compensation from one of the manufacturers as a result of failure provided you are within that 5 year ultimate window - i.e., because they deal with so few claims it's not big dollars to them so they'll appease to move on.
The actual manufacturing and its quality control is also another element into the durability/serviceability of STs (and any tire). I've seen many argue the "built to North American standards" or "built to US specifications", but with 3-5 year design lives that's not challenging when you also follow the laundry list provided with the ST tire maintenance and warranty guides. IMO, just all means of wiggling out of more responsible designs. Further, I have put my own two feet on the floors of tire plants in several parts of the world, and I would say that you see very little difference between plants in the same socioeconomic region regardless whose name is on the shingle. Frequency of quality control checks and testing is wide, and batches from a single production lot can differ. Only takes a few degrees of off-spec temperature in the Banbury to produce an inferior compound from the finest of constituents. Then with modern tire building done in a two-phase process, the final curing stage is critical and relies on careful temperature and pressure control to aid the chemical reactions along. Slight variation, inferior compound, and contaminants (even worker sweat) greatly effect this final, critical step and failures because of this appear no different that overload/under-pressure delamination...
There's no reason that a better trailer tire cannot be designed... The EU requires a better standard to be followed, but the market is far less and there's few sizes that work with North American trailers. Manufacturers just don't see the need or demand to improve.
Alright, now okie joe, I apologize for my part in rolling your topic down the sidebar of STs!