A jackhammer in the wrong place at the wrong time *can* bring down a structure. Resonance *can* destroy a structure - see the Tacoma Narrows disaster.
Witness on Fox says that it wasn’t an explosion that he heard/saw, he saw the long span bend and shatter in the center and give way - the actual support pylons were not involved.
“he saw the long span bend and shatter in the center and give way”
It could be that the road deck that was being replaced HAD BECOME critical in holding the bridge together. If rust or failure elsewhere shifted the loading factors and the deck took up the slack...then they take apart the deck to replace it. Bam, it comes down.