Terrible advice. Eventually you get a reputation which means nobody will work for you, or worse you get people who deliberately make themselves indispensable in ways which are harmful to the company. For instance avoid sharing critical info that gives you an edge. Sabotage other employees to get ahead. Stuff like that eventually led Microsoft to fall behind as they developed such a toxic culture.

Before you know it you got a company made up of psychopaths ready to stab anyone in the back to get ahead.

One should not be loyal to a fault but loyalty matters. If not nobody will stick around and Tesla, SpaceX or another company when Musk really needs them.

I think Musk succeeds because of other talents which make up for these flaws. But sooner or later this will hurt him. Reputation is hard to restore once ruined.