2 things I can think of right off the bat are that changing schedules can be done per-person, per-industry, etc. and doesn't have to be forced upon everyone whether it's good for them or not. Another reason is the technical difficulties of readjusting all time keep devices, scheduled software, etc. is a nightmare that should be avoided if you can. It's hard not to see that adjusting individual schedules is the easier and more effective implementation.
This reminds me of the idea that we could cut traffic if we staggered office hours. In theory it would work but in reality businesses don’t operate that way.
I feel fairly confident that the end result of this would just be that everyone changes their schedules together. Too many industries are linked.
