You seem to be conflating “working 20% fewer hours” with “producing 20% less value” While there are surely some jobs for which that holds, for many jobs fewer

You seem to be conflating “working 20% fewer hours” with “producing 20% less value” While there are surely some jobs for which that holds, for many jobs fewer hours amounts to a more compact and efficient worklife. Many people can attest to that from personal experience as both a worker and employer. No mental gymnastics involved.