It seems unlikely "physical AI" will be a complete bust but the post you're replying to is positing that fewer people will have money to spend on their services.

Because we have a largely paper pushing service economy and so the guy who's plumbing a luxury condo is dependent upon the existence of some overpaid javascript monkey who the builder/financiers are counting on to buy the condo when it's done.

If you automate the paper pushing what happens? Jeff Bezos isn't gonna buy more condos.