The only question I got is: why we as humans cannot fix this by having a proper calendar system that actually reflects the world and does not have these flaws?
The world is irregular (Earth's rotation and revolution durations vary) but we want regularity in our calendars and clocks. That's the source of the problem.
What do you mean by "actually reflecting the world"? If you mean using objective criteria of some sort, how would that help deciding if the week starts on Sunday or Monday, or what days of the week are to be business days?