Why? Metals are addressed at the end of the video. Metals can be thought of in the same manner except with complex orbitals that host multi-polar contacts with neighboring atoms.
In the lab, electrical conduction transmits charge but does not transmit torque.
The proposed mechanism would transmit torque but not charge.
Molecular orbitals are a useful tool when studying, well, molecules. But, it is a simple model that doesn't capture the full complexity of reality. In particular, it doesn't work at all for metals.
I think the poster is referring to the "electron gas as charge carrier" but personally I'm not exactly sure how things fit together.
Charge is symbolized by directional momentum of rotation here. Transmission of momentum indicates arc'ing of current.