"Most employers" definitely don't allow flexible working hours. You have to be in specific sectors – basically just "modern" tech companies – to have that privilege. And that is a very tiny slice of the working population.

Because most people don’t have that degree of flexibility. When I was commuting I’d have been happy to have double DST or whatever you want to call it.

With flexible working hours it works in both directions, so @ndr42 can also wake up an hour later for his health and performance :)