Just my two cents.
I have some experience conning ships under bridges (to be fair, nothing over 20,000 tons). A ship is nothing like a car, bus, or airplane - in how it is powered, turned, or controlled. Many monday morning quarterbacks in the press may as well be asking "Why didn't the train stop? Surely they could see the car stalled on the tracks?" Nothing is as simple or easy as they imagine. Those of us who have been there are more likely to be thinking "There but for the grace of God go I". When things go badly wrong on a large ship, you are playing catch up and often lose.
One thing is clear, few people understand what a maritime pilot is. They do not drive or command the ship. They are local experts and, technically, only advisory. Except in the Panama Canal (or while entering a drydock) ship's company are responsible for controlling the ship. That said, pilots often all but have the con, ships can simply do whatever the pilot says (but if it goes wrong, bear responsibility for whatever mishap may occur). NTSP will sort it out, but I've seen nothing that indicates either the harbor pilots or ship's company did anything wrong and they clearly did some critical things right. Fun fact - maritime pilots are far more likely to die on the job than police officers, getting on and off an ship in open water isn't ever completely (often, even reasonably) safe.
As someone said, the insurance industry will probably have a lot more influence on outcomes than U.S attempts at regulation of foreign flagged shipping, and barring foreign shipping from U.S harbors would mean ending more than 90% of our foreign trade.
I've had a few extended tug escorts, but only on ships with compromised rudders or other control or propulsion problems. Traveling with tugs made up is no bed of roses either, more moving parts is more things to go wrong and no guarantee you can stay out of trouble. Making up or casting off a tug alongside in open ocean is in itself a dangerous evolution.
The bridge had dolphins (visible in photos) but the 4 structures present provided limited protection, and only from a very narrow approach angle. Better protection for bridges is something to look at, but protecting a bridge from a ship that weighs as much as 10-20 loaded freight trains (and doesn't collapse on itself like a derailed train) isn't trivial. The situation reminds me of standards for nuclear power containment structures (which had to be rewritten, but not retroactively, when jumbo jets came on the scene). One of the things we were very aware of fifty years ago is the number of everyday hazards we accept much greater risks for than the worst case scenario fault trees for nuclear power safety. Modern society has trouble treating risks rationally - falling haystacks, for example, kill more people in the US than sharks, rattlesnakes or lightning.
Bottom line is, the ocean is a dangerous place and things sometimes go wrong. Odds are, that will sometimes happen in a bad time and place, and we can usually improve the odds, but never beat them entirely. We can probably do somewhat better than the former Key Bridge in several respects, but nobody necessarily did anything "wrong" and even with extreme measures and investment the risk can't be engineered out entirely.