I mean you're not wrong, but its also a larger societal thing which ends up meaning government who negotiates such things. Its not just work, but school start times and bus schedules, public transport times, parking fees/times. It balloons out a bit, so its easier to have some official stance. However, it doesn't have to be federal, and could just be local municipal governments.
In general, though. Yes, individuals could just shift what they do, and this is exactly what humans did for a long time. The industrial revolution changed us so that we needed to coordinate and regiment societal schedules, and here we are now.
I was also reading an article about nutritional quality of food itself has been declining over the last 50 years. So to get the same nutritional amount, you need to eat more food period.
There’s also bigger systemic issues about food access that is driving people to “choose” it. Lack of time, cost, availability, transportation all factor in that are beyond a simple idea if a person having a pure choice between two equal (or even somewhat equal) options.