The fact that this piece spent a lot of time vaguely implying that the Betz limit can be beaten is a testament to its insincerity. The entire point of that equation is that it applies before any real-world concerns are involved.

There are a few good points here (e.g. per-field profit is a different goal than per-rotor efficiency), but it feels a lot like an out-of-field expert assuming that no one in the field has ever been creative.