You seem to have missed that if healthspan is increased along with lifespan, people will continue to be productive later in life, will retire much later - or not at all. If you look at the current demographic age groups, the 40-60 range is most productive. Extending that span will make education less expensive per productive year working. Given that people contribute into pension plans through their working lives, they have a longer period to 'grow' that pension.

The major expense in medical care is chronic diseases. If aging is eliminated, these will be as well.

I see the major issues being overpopulation and people at the top not leaving and so leaving room for younger workers to advance.