This is a terrible strawman. One could easily argue that Boeing should pay their employees enough so they could afford plane tickets to fly in Boeing jets. Comparing a commodity product to a commercial product like this article does is narrow and silly.
The point is that the amount of money that your workers are making, does not have any significant effect on the demand side of who buys your product.
If your workers make up ~1% of your customers, then them making more money to buy you product, could only really make you around 1% more money.
The argument is just completely nonsensical, that you could spend 100$ increasing a worker's wages, and that is somehow going to get you that 100$ back, because they buy your product.
Instead, you are only going to making back, like 1$ (Because they are less than 1% of your customers). It is an obviously false argument, that becomes apparently if you even do any back of the envelope math at all.
And this is without even taking into account things like revenue vs profit. IE, even if the workers give you back all the money, the materials of the car make up a significant percentage. So, if you pay someone 100$, they give it back to you, you now have to spend 60$ on materials, and you now only have 40$ left.... so you are down 60$.
"The point is that the amount of money that your workers are making, does not have any significant effect on the demand side of who buys your product."
This is a class issue. I imagine Henry knew that. Workers must be paid well. All workers. Or the ruling class (Henry's class) will wither and die.
This is a point the current ruling class has forgotten
The line about wanting his employees to buy cars is obvious propaganda, but hard to argue with lacking the truth it was meant to distract us from. The truth was not obvious, but required more facts, which the author supplied. So, now we are equipped to put Ford's line to bed: he had no particular desire for his workers to live well, but did need them to stay on the line.