Perhaps the feeling is that in a competitive society (which most of us live in) as long as things aren't collapsing I don't see why a plumber/doctor should care if a bunch of lawyers and software devs will be out of a job. They will become relatively wealthier even if their income is taking a hit. Their purchasing power should rise if most of white collar work is collapsing.

Yes, widespread automation of knowledge work is unlikely to decrease total production, so all the goods and services people currently demand will still be provided, but the power dynamic of who is consuming and who is providing might flip around. So a bunch of formerly upwardly-mobile people could end up at the bottom of the social hierarchy while others whom they used to look down upon will be able to afford servants for the first time in their lives.

They would become wealthier in a real sense, since the services that used to be provided by the scarce labor of lawyers and software devs would now be far cheaper. In fact due to Jevons' paradox, even lawyers and software devs would enjoy far higher living standards due to AI. The boost in efficiency just creates a spike in demand for the remaining human component of the job, no matter how tiny.

That kind of thinking might work if 1, or 5, or 10% lose their income. If 50% do, there's revolution. And that's not great for anyone, including plumbers and doctors.