I overheard a manager for a state agency talking about hiring for low-level jobs. People in retirement or with master's degrees were applying because they are willing to do what is needed to get their foot in the door. Getting a job is very hard and people are going to start or, in the case of the retiree, go back to work, at the very bottom of the pay scale. The worry for managers is that such people are not going to stay. So the question is: Are you going to hire an older or even retired person? The answer might be "yes" because that person may be willing to work hard at a new skill and in the end may fit into the workplace better than ever imagined. They see the benefits of making the organization they work for better. Or that is what the LSU study suggested.
Note: You might also want to read "Age is Just a Number". This article from the Society for Industrial and Organizational Psychology is very revealing. Even the perception that older workers are more costly is challenged.