People that proposes to replace local timezones with global UTC must be living in europe where it doesn’t impact them much if we do abolish the timezone. Now consider people that lives in the other side of the planet. Most people are active during the day, yet for them, the day will end right in the afternoon under the new system. So you tell your friend “hey, let’s meet tomorrow”, then your friend would be like “do you mean this afternoon, or in the morning next day?”. No way people living in the asia pacific would accept this without military intervension.