The article seems to imply that there's a large imbalance between employer and employees, specifically that companies go to great pains for employee retention.

The article seems to imply that there's a large imbalance between employer and employees, specifically that companies go to great pains for employee retention. Employee retention is expensive and it could be construed that the article writer equates perks with 'loyalty.' So, to answer your question: all the time. By continuously offering perks they remain 'loyal' to you.