Good on her, and whenever I see/hear folks say that hiring younger workers is cheaper overall for a company, I very simply wonder if they have ever actually worked for a good experienced older worker.
An older worker can get things done in an hour that can take younger workers a day (or even longer!), and thats not even including having someone come in and fix issues with the younger person's code. The older person can mentor younger people, and will ensure that the younger workforce will turn into better workers.
On top of that you hit on the other thing, they are often more mature, have a better work life balance, and know what they want. This tends to mean less personnel issues, the person is much less likely to burn out, and the person will stay there longer.
I would happily pay 3-4x for that more seasoned person for the quality work alone, but there are so many reasons to have older, more experienced people in your company.