> The author should expand on why he thinks it is actively bad that some people are getting more while everyone is better off anyway.

Scenario 2: I have a hunch the owner does not like that, even if the owner gets richer that way. Instead, the owner and the worker could also decide to keep the workers key at 75%, splitting all the new proceeds between them with the same distribution key. This sounds like the most stable option.

Scenario 3, aka reality. The worker's labor is getting worth more, but the proceeds from this increase goes mainly to the owner. Sidestepping the fairness issue, this is a problem on a macro-economic scale. Wealth will accumulate within a few families who invariably are going to thwart the democratic process to gain more influence than one person=one vote. The system will tune to the needs of a few families, it won't optimize for a global maximum. You can look at the healthcare industry in the USA to understand how a local optimum is disastrously lower than the global optimum. Which by the way has effects on the economy itself (workers will choose to stay in a bad job out of fear for medical costs, or they have to live in bad health, etc). Sociology and economy are deeply intertwined.