There's a handy chart out there that plots change in worker productivity and change in purchasing power by income percentile over time that answers this in a single graphic.

If a task normally takes 10 minutes, and an employee completes it in five, is that a donation of effort?

Is it theft to titrate the productivity of your labor to fit the rate of pay you receive for it? Employees do not get paid more for effort that exceeds par.

If I get paid $7/hour, I can easily reduce my productivity until one hour of my labor produces $21 for the employer. Or maybe I work two hours to produce $160 and slack off for six.

Two consecutive generations of not being rewarded for contributing additional effort for the benefit of the company has taken its toll, culturally. Nobody is willing to uphold a string work ethic for an unethical employer.

The employers burned through all their credit with labor, and are trying to refinance by redefining all the rules. It won't work. It's time for them to pay up.