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I know at our workplace heating on Monday mornings has to start several hours earlier than on Tuesday because the office lost almost all of its built-up heat from the previous Friday. I also know that they continue to run the heating on holiday-Fridays/Mondays because if they don't by the following Monday/Tuesday, the temperature will drop too low and could damage equipment.
But I guess the answer would be that people can't abide the thought of one uncomfortable minute in their own home, and don't bother figuring out how to program the thermostat.
If you turned the heat off at 7am as you left for work, the house would probably be below 60 when you got home, and take most of the evening to reheat, only to be turned back down again at bed time. I don't know anybody who manually does any of this - at best, they have a smart thermostat that lets them schedule home/away time or uses cell phones as presence sensors. And even then, they'll lower the heat 5-8 degrees, not turn it off completely.
If you leave the heat on during the day (and that can be a few degrees lower) then you can keep the structure warm and avoid all that evening heat loss and cycling. But only if you have good insulation. Otherwise you’re just dumping heat out into the environment. The other factor is how cold it is outside, if the temperature gradient is steep then it’s harder to contain hot air.
But thermal mass can be a big thing. My house isn't even all that well insulated, and when it is 0º F outside, it only drops about 10 degrees if the furnace is off all day.
