There's nothing gentlemanly about ripping off people who work for you to the tune of millions of dollars.

That's not a gentleman's agreement. It's the exact opposite when you actually consider the target of abuse in the agreement: their own employees, people, whose lives they were seeking to actively harm.

If they'll actively, illegally, seek to harm their own people, who could question whether they'd illegally try to harm a competing company? It makes perfect sense that that would be in the realm of consideration.

You can also see it differently: When the supply is locked out, they have to compete on price harder from the beginning and have less opportunity to fire. If there's an oversupply, of course it's a bit different.

>Fair point. Still, a gentleman's agreement between frienemy titans of industry (though illegal) is understandable

What? No it's not understandable. It's wage fixing and is totally immoral; it works against everything a free market is supposed to be. You might as well move to the communist model and have everyone paid $xxx (hyperbole but the point isn't that far off it).