From an evolutionary point of view, I wonder if it has to do with giving them plenty of evening time for sexual activities. Especially since 30 used to be old age at one point in our past, so teenage years were the childbearing years…
Luckily, my state understood this and our school hours were like 8-8:30am to 3pm. Still kinda early, but way less of a kick in the teeth as states that make their kids come in at 7am and out at 2pm.
The mega travel center in the South Eastern US, called Buc-ee’s, does have these indicators. However the last time my family was there, my wife encountered a Karen who was concerned she couldn’t tell which stalls were open and my wife pointed out the red occupied/green unoccupied indicator on the locks and she was like, “No, I don’t know, I’ll wait for someone to leave.”
Not without rooting it or the manufacturer including a custom option for it, but if it has adaptive charging, you can set an alarm and it will charge the phone up to 80% and then wait to charge it the rest of the way to coincide with the alarm so that it isn’t at 100% for a long time.