Aka, it was a jobs program.

It was a Keynesian anti-cyclic wealth distribution program.

The jobs did come and go as necessary to maintain stability. It was reasonably well paid, from money collected taxing the luckiest farmers at the good times, stored as a community project.

It's really impressive how the Egyptians created this kind of organization and maintained it for thousands of years, when no government seems to be able to maintain something similar for a decade today.