Why didn’t they just blow the bridge before the Germans got there?
They planned to blow the bridge anyway. They had it wired well before the Germans got there. They explained that the Americans just needed the deep water port for their ships, but the Germans needed the two remaining bridges in France to attack the American flank. So it stands to reason that they didn’t have use for the bridge.
They planned the blow the bridge after the Germans overwhelmed them. The bombing run from the P-51s seemingly did not care that the bridge was intact or not, as they were going to strike the tanks if they were on the bridge or not.
https://www.reddit.com/r/movies/comments/mjgrxh/in_saving_private_ryan_why_didnt_they_just_blow/