Think about it, daylight savings time is less than pointless, many places aren't in their "actual" time zones, and instead have their time zones decided politically, and even regardless of all that, what each hour means is entirely personal based on your habits, job, friends, circadian rhythm, etc, so 9PM might be super late to one person, but still pretty early to others. Cutting out time zones, people would pretty easily adapt to what hours mean where they live.