That would imply everyone living in the same time zone wake up at the same time, go to bed at the same time, etc, where this is clearly not even close to being true. If it's too late to start a monopoly game for you, you can just say so
Shops, schools etc should just have hours that make sense for the local solar time anyway
You seem to have missed at least part of my point. To keep with the monopoly example, you already can't assume that it's too late for anything or there's time for a game of Uno, because people have different rhythms and there's variance, so even if you know it's 2300 for them it still doesn't solve the problem, you are just making an assumption which may or may not be correct on any given day for any given person.