I'm a contractor. I have to pick up the phone any time of day or night or I lose a client. Most of my friends and family work at varying levels of healthcare provision. They can't just send everybody home on Friday. They can't even do that at the weekend. And retail faces similar issues. Plus they're still fighting online sales.
Estate planners are basically the slowest possible service. They could probably work a two day week and let the answerphone and inboxes pick up the grunt work. It's neat that this works for them, but —and this isn't just jealousy— I don't expect this to become widespread any time soon.