> I was waiting behind people with batteries that were 92%, 94% and even 97% full, as I could see on the charger screens. Still, they stayed there. I made my own situation worse by giving up on one location and going to another with more chargers, but there were even more EVs waiting there.

It sounds like marginal charging past 80% is too cheap per percentage point. If you want to encourage throughput, you have to make it expensive to be a "hog" in TFA's parlance.