Assuming there is no difference in the structure, there should be no difference in structural strength. (How's that for stating the obvious?)
But when you are talking about air v. coil, it may be that the manufacturers are concerned about blown seals and other internal issues, not just structural problems. Air springs have come a long way, and yeah, we've got the Fox 36, Air boxxer, etc., but still, that might explain some of the examples here.
I know you wanted a more philosophical debate on what "trail" means but I keep coming back to what I said in the first place: Ignore what they call it and figure out the purpose and capabilities of the product.
But when you are talking about air v. coil, it may be that the manufacturers are concerned about blown seals and other internal issues, not just structural problems. Air springs have come a long way, and yeah, we've got the Fox 36, Air boxxer, etc., but still, that might explain some of the examples here.
I know you wanted a more philosophical debate on what "trail" means but I keep coming back to what I said in the first place: Ignore what they call it and figure out the purpose and capabilities of the product.