Yes, I'm sure all the wage slaves who are suddenly forced out of the labor market that was barely allowing them to scrape by paycheck to paycheck will suddenly start creating new businesses and become investors in new technology and not just become homeless leading to a massive increase in diseases/crimes of despair.
If (and it's a massive if) what passes for AI these days gets good enough to replace any substantial number of workers it will be a disaster.
Some of the projects we've done would have required 4-6 additional people, but realistically, pre-ai, we would just not do the project or we would do it over a period 3-4x longer.
There's just so much to do.
As far as I know, that's how the lump of labour fallacy actually works! There's an equilibrium between supply and demand for labour such that workers are (more or less) choosing the best jobs they can find. There's infinite demand for labour, but not at any price, so demand destruction of the best jobs can still happen. There will be infinitely more jobs, but they won't be as good as the ones that were destroyed.
Of course, demand creation for really good jobs can also happen. What the GP is saying is that they believe demand destruction will outpace demand creation for really good jobs and everyone will be forced into less desirable jobs. I don't see how this is inconsistent with the lump of labour fallacy.
Company stock value goes up when they lay off staff. Next quarter shareholder maximization is the goal. AI and layoffs is the strategy to get there.