I follow your logic, but there's a bigger picture. Entrepreneurs go into business to make money. To make money, entrepreneurs have to employ people who provide value to the company, i.e., a positive return on their investment. If an employer chooses to limit their applicant pool to such an extent that they eliminate the most productive employees, based on immaterial criteria such as marital health, then they are chopping off their nose to spite their face.
Business decisions are primarily (almost exclusively) based on profit, whether on a strategic or tactical level. No successful company is going to winnow down their employment candidate pool to such an extent that they hurt the bottom line. That's the bottom line.
We have a glutted labor pool. This is evident in the current average wage paid versus previous wage paid in a given market, and also acknowledged by many analysts. Workers will need their jobs and will endure anything short of not being able to look at themselves in the mirror shaving.
So has the abuse threshold gone with people in history, from what I've read.
I'd be more than happy if you could talk me out of that dark prophecy. "We're America. It can't happen to us." can't be valid with the massive changes to the original founding structure made during the 10th and 20th centuries, I'll warrant.