I agree with all this, except there is no plan B. What could plan B possibly be when white collar work collapses? You can go into a trade, but who will be hiring the tradespeople?

The companies who now have piles of cash because they eliminated a huge chunk of labor will spend far more on new projects, many of which will require tradesmen.

Economic waves never hit one sector and stop. The waves continues across the entire economy. You can’t think “companies will get rid of huge amounts of labor” and then stop asking questions. You need to then ask “what will companies do with decreased labor costs?” And “what could that investment look like, who will they need to hit to fulfill it?” and then “what will those workers do after their demand increases?” And so on.