Laws are for the lawless. Laws protect the innocent from the actions of the lawless. That is not to say all laws are good laws, nor that good laws are always fairly and effectively enforced.
"What could possibly go wrong?"... If everyone stopped on red and went on green, nothing, and there'd be no need for a law making it illegal to run a red
light. However, in many places red
light running is epidemic. I make a practice to look both ways before entering an intersection, even when I have the green.
A few years ago I T-boned a small pickup truck that rolled right through a stop sign because the driver's "senses" told her the road was clear. Good brakes slowed me enough from 55mph to prevent injury to the two boys riding in the open bed of her truck (which her "senses" apparently told her would be okay, too). Good brakes limited damage to my vehicle to $10K, a good thing because her "senses" told her $10K property damage liability coverage is good enough, and the State of Arizona apparently concurs.
Imagine the same scenario if I had been pulling an unbraked 1500 pound trailer...
If everyone followed current best towing practices, there'd be no need for laws. Of course there will always be disagreement about what are "current best practices." It certainly keeps this forum going! But what any manufacturer did 40 years ago is not relevant. There was also a time when cars came without seat belts.