It's fake. The end.
Speaking as both a former boss and employee--and nearly all bosses are a combination of the two--it sounds like you're making an argument for job-hopping. I have no issue with that--when it's time for someone to go, it's usually best all around for them to go--but the negative is instability, not disloyalty. I've never met a boss yet who enjoyed hiring and firing, and when people leave, that's what you're left with. I always found as a boss that if I showed loyalty to my people, they generally showed it back, and I never stayed with a boss myself who didn't. Maybe things are different in the service industry--where the stakes are lower on both sides and a certain amount of job-hopping is inevitable--but in the professional ranks, your idea of a boss isn't nearly as powerful, and the employees she manages aren't nearly as weak as you say. Loyalty should be--and I think usually is--a two-way street.
‘loyalty at work is distinct because of the way it intersects with power: It functions differently between two equal actors versus between a boss and an employee’