While it's true that putting up with overly-difficult people can be good for business, this creates a race-to-the-bottom situation and there's no reason it shouldn't change. Someone's bad day is never an excuse for abusing service workers.

For what it's worth, I was a service employee who deprioritized these people and I can tell you I'm certainly not working customer service at Comcast now-a-days... which is a reference I don't even understand (I know what Comcast is but ya...).

Tangentially, I feel that there should be a form of conscription where everyone is forced to work at year or two of customer service in their teens. While I'm sure it wouldn't discourage everyone from being a prick, it could certainly help.