But 40 hours of “work” is poorly defined. If you had everyone digging with spoons on your construction site, then you might need 100 people at 40 hours per week. If you have everyone shovels, you would only need 10 people at 40 hours a week. Do you want to tax shovels for “taking the job” from 90 people?

Should we tax bulldozers because they take away jobs from people using shovels? What about farm equipment, since they take away jobs from people picking fruit by hand? What about mining equipment, because they take away jobs from people using pickaxes?