ECONOMIC POWER GROWS OUT OF THE BARREL OF A GUN *
Answer - Cause we would all be fired if we tried something like that.
What does it mean to be fired? Tossed out in the street, evicted from the workplace - bodily chucked out if need be. What if you refused to go? If management can't do it, they call security. If security can't do it, they send for the cops. If somehow you kept the cops at bay, then here comes the army. At this point, a couple of you might get shot just to make sure you understand who is really in charge of your life.
Thus, capitalism is in the final instance based upon violence, and all wage labor is ultimately forced labor.
Imagine a situation where the repressive forces of the state ceased to exist, or were converted into popular democratic forms - such as a workplace-based militia. Without the threat of boss violence, there would be true equality of contract. Workers would be free, if not to totally dispose of their labor power according to their wishes, at least to be in an equal bargaining position with their employers. They could decide which hours they worked and how the work was organized. They could demand "an opening of the books" when the bosses claimed there wasn't enough in the till.
For sure, the bosses wouldn't like that. Pushing people around is one of the joys of bossism. The more humane and decent among them would adapt to the new egalitarian situation, but most would not. They would flee to those countries where bullying and exploitation was still the norm. The rest of the world’s economy would take on an ever-increasing cooperative nature. With freedom, capitalism disappears...
* According to the Great Squeeker, Mouse C. Dung