The Baltimore bridge collapsed due to a domino effect - Physics and Mathematics. A localized impact, like the one occurred by the merchant ship, was enough for the consequences to have repercussions on the entire structure in a very short time.
If this happened, the cause is also to be found in the design criteria adopted in the past, which did not adequately consider the concepts of structural robustness. It is difficult to say how many bridges like this have been built: "it is a widespread typology, but this bridge still has some singularities"