Not every hour of the day is the same hour

Attention has a shape across a day, and it is not flat.

Anyone who has tried to do something demanding late in a long day knows that attention is not evenly distributed. There are hours when a hard problem feels tractable and hours when the same problem feels like a wall. The hours are the same length. What differs is what you can bring to them. Most people know their own pattern roughly, in the way you know which chair in the house is comfortable, without ever having used it to make a decision.

Because the calendar treats all hours as interchangeable, we routinely put the hardest thing in the worst slot and then judge ourselves by the result. The demanding piece of work goes wherever there was a gap. The gap was at four in the afternoon because that is when everyone else had stopped asking for things. So the work that most needed capacity got the hour with the least, and the conclusion drawn was about the person rather than the placement.

There is no universal schedule here and no rule about mornings. The point is smaller and more useful: your pattern exists, it is reasonably stable, and you almost certainly have never used it as an input. Once you do, the same week produces noticeably more without anything being added. You have simply stopped spending your best hours on things that would have been fine with your worst.