The elderly cost more, do less, and take more, return less than any other culpable group on the planet. Societies that would kill or exile their elderly did do better than those who attempted to care for them long beyond their usefulness. That said things are very different relating to money, resources, and ethics so it doesn't really matter.
Even though they are retired they still work for our society, most of elders run a store, have a small farm, babysit, do volunteering or help in other ways, they have a retirement but they worked for it, as are we working to support ourselves once we get old too.
Sometimes, the elderly can help younger people when they need help with something, because they have been through a lot of things, and they know a lot of different tactics to use when people are confronted with certain problems. So they are not a drain because people can benefit from their knowledge.