It is the same time everywhere.

We just make up what time it is to make our lives easier. There is no particular reason that we need to use any specific time anywhere or all can't be on the same exact clock everywhere. We choose to do it because it can be useful.

Lets say we all agree that noon is when the sun is highest in the sky. No matter where you are, when the sun is highest, its noon. Of course noon in New York, is gonna be hours behind noon in London. This is how it works now, more or less.

But what if we didn't care where you were on earth?. What if noon was when the sun was highest in London, and everyone else used London time. For New York, the sun will be lower. But it would still be noon

Does any of it matter? Does it matter that the sun is lower in New York and its noon? Couldn't people in new york just say start their day at 1pm instead of 8am, then go to bed at like 3am?