Earlier quoted context omitted.
The notion that employers are unfairly collecting economic rent from their employees doesn't require it to be a zero-sum game.
Who’s paying less than they expected in today’s market? If anything it’s the other way round right now—lots of people are taking jobs for more money than they expected.
What matters is 1) how much wealth any given employee generates, and 2) how much of that generated wealth they retain. Anything that doesn't end up in their pockets, and is not a business expense otherwise, is economic rent collected by their employer.