Of course we can’t know what happened, or know motivations or decisions that were made. We will not know for a long time.
However, I have to counter the idea that unquestionably dangerous and potentially criminal decisions are never made by those in charge. Look up Buffalo Creek. Look up Bhopal. People in decision-making positions make choices that are clearly cutting corners all the time. How do they sleep? I have to assume that when they make these decisions, they cross their fingers and lie to themselves–that nothing dangerous will happen. That no one will die.
I have no idea if anything with this bridge is because of cost/corner cutting decisions. We won’t know for a long time. But I just can’t accept the statement that people don’t make dangerous, cost-saving decisions in real life. Of course some do.