Case in point ...
I just checked tomorrow's sunrise time for two different places in the Eastern Time Zone. The sun will rise at 7:12 AM tomorrow in Boston, and at 8:04 AM in Fort Wayne, Indiana. Both of these cities are in Eastern Time, but they are 52 minutes apart by the sun's rising and setting.
I've long suspected that one of the reasons Daylight Savings Time was originally instituted was that many of the country's biggest cities were in the far eastern areas of their respective time zones -- Boston, New York and Philadelphia in Eastern Time, Chicago and St. Louis in Central Time, etc. This means the sun rises very early and sets very early in these cities compared to the rest of these time zones.
Daylight Time started in WW2. People liked it. People like it when the sun sets later in the day. People can do things after work when the sun has not set. You can mow your lawn. You can garden. You can wash your car. You can drive home in the sunlight.
You posit a fascinating theory.