Very good point.
#1 IMO, yes unions are partly responsible for every problem (seriously). In their heyday they grossly interfered with market forces -- after doing great things for labor.
#2 IMO market forces should (more or less) set executive and labor wages.
The topic of market forces is definitely germane to your suggestion IMO and interference can be two-way. And "unions" are not limited to labor, IMO.
I would ask what of the interference with market forces today that affects solely labor wages; to wit, a domestic labor glut and labor arbitrage?
Why say interference and how did it happen?
IMO due to non enforcement of immigration laws the labor glut is artificial. Did it just happen that there is virtually no enforcement? I don't think so. It's what business and both political parties wanted.
Adding to the glut of labor, what of labor arbitrage? Mostly it is due to improved transportation and IT-enabled cross-border outsourcing.
But there is also taxpayer-backed cheap risk insurance and other government-sponsored services provided to corporations to encourage doing business over there.
That too is a business / two-party endeavor (union?). I think that it's fair to say that "globalization" shifted into high gear during the Clintons' administration.
I sort of hate the word fair, but is it "fair" that business and both parties have seemingly (IMO) moved beyond being Americans?
Are we on the road to a Davos world led by a union of business and both parties?
You noted above that "Since the US is no longer, and never will be again, a closed market, our companies cannot raise prices to cover these [labor] expenses."
I think that this is all germane though somewhat wider than the dollar value of executive v. labor wages alone. But I appreciate your point about focusing on someting so we can all at least agree to disagree on something. Then move on.
(I don't recall seeing anyone asking for a "closed market" mostly it's stop free tradin' away technology, wealth, and production, especially to China. Stick with what has always been good for us, real free trade.)
In Econ 1A everyone has to memorize the definition of pure capitalism --a market where no one buyer and no one seller can affect the market price. This was the case of the labor market before we had factories. Back then we had as many households buying handywork as there were shops selling it. When factories were invented, suddenly the labor buyers (factory owners) were calling the shots. This stopped when the workers formed Unions and made the number of labor buyers equal to the number of labor sellers. The unions restored the pure capitalist market.
Things keep changing. Over the last few decades there's been a big shift to small non-union businesses. Now, unions are neither good nor bad; they're irrelevant --a thing of the past.