I like to compare modern LLM to Excel or calculators in the past. Some years ago a company would have an in-house team of accountants. Then came Excel and now a single accountant can do the job for 10 companies. Let's now consider programmer: currently a project manager oversees a team of programmers, most of whom are only responsible for mundane work of typing out code. With AI a single worker will be able to perform more productive than that team of programmers, because they will offload the boring work to AI and focus all their attention to what AI is perhaps incapable of.
What this article is really saying, which I agree with, is that AI improves productivity ,just like perhaps the steam engines did in the 1800's. But this time the problem is we won't increase the output and let the workers work more efficiently and earn more money, because it's not manufacturing jobs which were limited by technology that this is influencing. It's office jobs, which the economy has a pretty much fixed demand for. Workers will not improve their productivity, they will just be replaced because their work can be offloaded to a machine capable of doing that same jobs better in every significant way.