Being an oversized hauler myself I can see several key mistakes.
1, while the trailer may seem to be the easy thing to blame, it is not. The trailer is the right equipment for the job, I have hauled similar tubes with similar trailers because the standard pole trailers cannot support the weight of the load as easily. Now I am not saying you can't use pole trailers or other types it is more cost efficient and accepted to use the lowboys.
2, his first major mistake was allowing his trailer to drift into the dirt and thus off the road which meant his lowboy is now lower than the roadbed. A simple way to avoid this was to place a pilot car ahead of you in the turn to stop any incoming cars and place a second on the road you are turning onto to do the same thus allowing you to use the entire road the turn on.
3, his second major mistake was hiring a pilot company who didn't do their homework, also the truck driver should always verify routes himself to ensure all laws are followed and proper authority is notified. In this case it appears the pilot cars were inadequately prepared for this intersection and probably worse, didn't warn the driver of the truck that his tandems were off tracking into the dirt and thus off the road, which they should have done.
4, just because other trucks ahead of you made it doesn't always mean you will. I think this driver got a bit cocky and tried to one up the other drivers by turning shorter or flying blind, i.e without proper setup ahead of time with pilot cars strategically located to stop traffic.
Whatever happened here, it is mostly human error not equipment failure or inadequate equipment that played into this situation here.