Time to move on? The case against daylight saving time 13 years ago
You are misunderstanding how it would work. People would still be awake when it's light out and asleep when it's dark.
Instead of everywhere starting their workday at 9am UTC like you're imagining, London would start their workday at 9am UTC, New York would start their workday at 4am UTC, Los Angeles would start their workday at 1am UTC.