If it weren't for our current economic system, having a glut of lawyers, doctors, scientists, engineers, etc, would be an incredibly good thing. For everyone.
Like, I get why a naïve opinion might be "the more engineers, the better" on the simple but attractive theory that more engineers = more stuff = better for everyone.
But what's the even simplistic theory that leads to "the more lawyers the better"?
And surely even a simple theory says "once you have enough doctors to provide healthcare to everyone, you're kinda done with doctors."
We already have things that aren't scarce and by assuming scarcity is a factor of value, we irrationally devalue them. Post-scarcity economic systems attempt to resolve that.
Look at the struggle the entertainment and journalism industries have had since the value they provide was divorced from distributing scarce print/recording media, etc. Disregard human subjective behavior, the rational behavior under capitalism before was to buy the thing you wanted, now it's to try to be a free rider, so that's what most people are doing, despite valuing creativity and journalism no less.
So, instead of being able to participate in an economic system that solves the problem of compensating the creators of non-scarce information, they turn to DRM and paywalls and other ineffective solutions to try to force their bits to be effectively scarce for the majority of consumers, and therefore remain valuable and prevent the free riders.
That said, a post-scarce economic system also shouldn't aim to be producing a glut of any one variety of professional, so it certainly isn't a good argument within the original thread.