What was needed was temporary center pillars right at the highway median strip. Once the tower and all the cables are installed you can test and adjust cables and test test test and remove the center pillars. And not be hasty about removing them. Only when you are 1000% sure it will hold minus the center pillars.
I spent several years performing structural dynamics work and studies for the DoD and the first thing I thought was why they didn't have temporary shoring placed at the Median until the support structure and the Cable Stays were installed and tensioned.
Always over-engineer and account for safety, even if the numbers tell you differently.