Because the wallclock time of the astronomical sunrise moves around all of the year. If you want the most daylight, you need to follow a sundial clock, not a wa

Because the wallclock time of the astronomical sunrise moves around all of the year. If you want the most daylight, you need to follow a sundial clock, not a wall clock. Since our modern society can't really function with sundials, DST is the compromise. If you don't accept that compromise then you will have less light during the summer evening or very dark winter mornings, pick one. Or variable winter / summer schedules, which are simply a much more expensive version of DST, with massive coordination issues. BTW, using sundial is biologically optimal, it does away with the shocks and lets the body adjust throughout the year. Here is an instance where technology change the world for the worst.