A post-mortem of what happened must look into the politics that drove the engineering. From initial appearances, failure began with decisions to require an artsy, landmark design, at huge expense and extra complexity, to market the college. Administrators wanted not to solve a need, but to look cool. There is obviously room in the middle of the highway for a center support and conventional bridge.
Testing and adjusting with the road open was idiotic and irresponsible, but almost assuredly driven by the politics of avoiding a public outcry over closing the road for 2 years. Contractors who get jobs are the ones who say “yes, we can do that...for the right price”. Trying to hold up a suspension bridge with one or two construction cranes was foolish beyond comprehension, but a consequence of reckless requirements. Why the main support mast was not built ahead to placing the spans is mysterious.
The non-engineers who insisted on these things will say they relied on others to make it all safe.
One small quibble, if I may. Traffic engineers are reluctant (and understandably so) to place columns near traffic lanes. Bad drivers have a way of finding them the hard way.