As he was the better TTer and far better on the gravel than those two, he'd not have needed to outclimb them to be better than them.You seem to be missing the point. Arensman already confirmed his potential by finishing 3 GT's in the top 6. So far Jorgenson has 1 top 10 spot. You may rate his 8th at the TDF higher than whatever Arensman showed, but he needs to replicate or improve on it.
And Jorgenson was not the 4th strongest GC rider at the Tour. Even without his crash and having done any work, he would not have outclimbed Landa and Almeida. You may value his work overall, and say he was the 4th strongest rider "overall", just like a few years ago you could have said Van Aert was one of the 3 strongest riders in the Tour, but that doesn't equate to 4th or 3rd in GC.
In a Landa role, I think he most likely would have finished 6th in GC. That is, if he and Vingegaard don't try to gain any time in the gravel stage. I do not think Arensman would finish this Tour anywhere close to the top-10.