That 'tired argument' is how capitalism works. So like it or not, an Engineer is paid the going rate.
The value of the automated system is clear. The value of the engineer is the automated system. Which might be quite expensive, but nothing like the value of its output.
I was trying to talk about the value the engineer produces from the perspective of their employer, which is separate from what that employer is willing to pay the engineer. In economics terms, I'm talking about the consumer surplus (the employer is the consumer of the labor the engineer produces, and has a surplus because they get more value than they are paying).
I called it a tired argument not because it definitely isn't true but because I'm tired of people shutting down unrelated conversations with it to look smart.
A simple scenario that shows these are separate concepts:
Suppose we have an extremely dumb firm that pays the engineer a trillion dollars to create an product that can make whoever owns it a billion dollars.
Suppose we have an extremely dumb engineer that charges a different firm $1 to produce the same product.
Suppose both firms are trying to sell the automation to a third firm. Their expenses are a sunk cost; this firm isn't going to pay the dumb firm that overspent any more. The value of the product is (generally) separate from your cost of making the product.
The value of the automated system is clear. The value of the engineer is the automated system. Which might be quite expensive, but nothing like the value of its output.