It's a matter of degree.

CEO-to-worker comp was 20-to-1 in 1965. In 2021 it was 399-to-1. [0]

CEO comp rose 1,460% from 1978 to 2021. Worker comp rose 18.1% over that period. [0]

>Your problem is the stock market punishes companies that don’t have cash flow

The idea that the company's sole responsibility is to "maximize shareholder value" has become a bit of a meme in its elevation to the status of some codified fiduciary duty. In fact, it's derived from the musings of a single economist (albeit a pretty influential one). No surprise that was uttered in 1970, just prior to the sharp increases in compensation disparity. It could be credibly argued that this canard has been used as the "moral" pretext for measuring and rewarding CEOs and shareholders to the detriment of workers. "Yes, we're redirecting trillions from workers to executives and shareholders, but you see, that's our moral obligation as a company with a single overriding missive".

So, used here as ostensible justification for suppressing worker wages (i.e. to avoid being "punished" by the stock market), it's a bit circular.

But, ironically, your positing it as credible rationale for resisting unions underscores its pernicious effectiveness.

[0] https://www.epi.org/publication/ceo-pay-in-2021/