You could overlay this map onto the enthusiasm for permanent DST and see a pretty good pattern. Those of us on the western edge of a time zone have a lot to lose in that scenario(9AM sunrises) where folks on the eastern edges would be worse off in a permanent ST plan (3pm sunsets).
Pretty much the real reason for the time change imo. If you pick a permanent time, there are winners and losers. So… we keep doing this dumb shit.