Never made an argument for all designers. Obviously the talent pool for any field is finite, and the best of that talent rises to the top. Good designers are being compensated increasingly well, hence "designers are becoming more valuable than ever."

Bad designers are even being given better and better paying jobs as the top talent gets poached up quicker and quicker.

What job you have (theoretically) isn't due to "absolute advantage" but "comparative advantage".

In other words, if someone else is a better designer than you, that actually has nothing to do with if they're going to take your job. They may have something better to do. An ML model isn't a worker no matter how good it is at painting, so rather than having a job it has input resources (RTX 3090s, electricity, maintenance engineers) but the concept is still important.