1. It's bullshit, wrapped in a "professorial" presentation.
The "logic" behind this, and similar, arguments is that "I won't hire workers because I can't make enough profit".
Well, maybe not enough profit for Mr. Greedy, but it'll be enough profit for the next guy. If Mr. Greedy is unsatisfied unless he makes a 30% return on his investment, let him be replaced by someone happy to make 20%.