> The reasoning was: If you force jobs to be filled by people who are not as good at them, we collectively get less work done. Assuming that work tends to be useful, that means we collectively have fewer resources available.

Now you're changing your argument. The people who are the "best fit" for a job aren't necessarily better at it. They may be worse at it but willing to work for less money. Which is where equality enters into it: You're making the assumption that it's better to transfer that money from the workers to producers or customers. But for something that done at scale leads to the destruction of the middle class, that assumption is false.