I don't view myself as coffee - if your employees are fungible resources, I don't want to work for you (99.9% of the cases, there may be exceptions, but they're just that - exceptions).
My post was about viewing the employer-employee relationship as a business relationship _when you are the employee_.
You also present now a distorted view about business relationships - they're about trust far more often than they are about squeezing the best price. That's it really - once I learn that I can't trust my employer to compensate me fairly, that business relationship is broken, and short-term money can't fix it.
Indeed, all business relationships are about trust. But they also are about business. I know of no other business relationship where the supplier expects that the consumer will pay him fairly. So what is so special about an employment contract, compared to all other businesses?
Oh, this is really easy to answer. For example, the fact that purchaser dictates the price, not supplier - to such an extent, that purchaser voluntarily and periodically decides to start paying more, without explicit intervention from supplier. Oh, and also decides to reward supplier with bonus payments when receiving good-quality merchandise.
But it's not about that - if you think about it, it's probably related to the expectation of exclusivity. Is there any business that is expected to exclusively supply to only one customer? If so, I'd suspect they'd be very concerned about that consumer paying them fairly.