What you're talking about is seniority, not loyalty. Someone can have 30 years at a company and still be not loyal if their heart's not in it, they plan to jump

What you're talking about is seniority, not loyalty. Someone can have 30 years at a company and still be not loyal if their heart's not in it, they plan to jump ship, they take advantage of others, they embezzle, etc. Seniority is length of time employed at the company. Loyalty is investment in and contributions to the work community. And that kind of loyalty makes a company a nice place to work, because what you have is a community of people who are invested in each other.