This kind of measuring jobs by efforts always ends up being won by an animal or machine. Even among humans, the guy digging ditches with his bare hands is putting in more work than the guy using a shovel.

It ends up being a stupid incentive structure, and is not a replacement for supply and demand in the labor market.

Physically the rock-pusher job is harder. Mentally the architect's. I'd say pay comes in based on demand. Do we have more brainy folks or brawny folks?