>> I recently moved back to Colorado, where for many decades it's commonplace for people to drive everywhere with their high beams always on

Don't they teach in the driving school that you should turn off the high beams when you see a car?

I remember I was taught to turn off the high beams when the car (doesn't matter if you are behind the card or it's coming from opposite direction) is approximately 300m away, or when our lights start to cross each other.

Also, forgetting to turn the beams on and off at night is a good indicator that you are slowly falling asleep behind the wheel.