Over here they are allowing a limited number of people inside shops to adhere to governments rules. Works pretty well and it is enforced legally. The same can work for gyms, etc. And don't forget: people who work from home can create their own schedule. They are no longer bound to a '9 to 5' rythm. From a biological standpoint there is no rule which says humans (like to) work best from 9 to 5.
Most people do not work from home and will not in the future. Things aren't going to be that radially different. Yes some business will realise work form home isn't that bad and will move a bit in that direction. But I'm willing to bet that in a few years time when this has all blown over, the world will on average look and work very little different to what it did 3 months ago.
Do you have kids?If not then you likely won't understand why a lot of the daily/weekly routines exist.
I have kids for over 2 decades. The youngest is getting on-line lessons. I've also been working from home for nearly a decade. The only reason to adhere to a strict schedule is when people really need to work together on the same item at the same time. Now think hard of where that is really really true. In the end the answer is likely meetings and team sports.
No, it's getting kids ready, dropping them off at school, picking them up from school, getting them to swimming and soccer and *insert other events here*, lunch is roughly midday, dinner roughly the same time every night, meals need to be prepared etc etc. Regular life routines, regular as clockwork for the majority of people.
As for the likes of gyms, majority of people don't like to go at random hours, or hours dictated by some social time scheduling guidelines. They want to go to their favorite class with their favorite instructors at the most convenient times to them. Before work, lunch time break, after work etc.
Same for say movies, most people are not going to want to go at say 10am on a workday on their own, they want to go at times that fit their schedule like saturday/sunday mornings or afternoons with their family, or Thursday which is release day, or Friday night with their friends or partner.
People will want to get back to this routine as soon as possible, and the longer they aren't allowed to do that the more pissed of people are going to be. They don't want a "new normal" and will not accept it in the long term, you'll see.