I agree. Unfortunately, its illegal, and the perps would go to jail. The union can get together to pit one company against the other, and that's entirely legal. But if the companies try it, they violate the law. Such is the legacy of FDR. This is not to exonerate decades of mismanagement by company bosses (I'm one of them, retired), but it does complicate the current strategy.
But the loophole would be if the the companies just choose to not bow down to the unions. It would not require an actual “conspiracy”, just that the management decides to do what is best financially for the companies...