This discussion popped two thoughts into my head.
First, the extension of life by some drugs (here we are talking V and CVD) for some of those being treated (yes no drug helps 100% of those treated) might mean an increased longevity which would then mean those subjects contracting some other condition (thinking things like AD, cancer, etc.) costing more money than just dropping dead from a HA.
Secondly, I'm not sure we can ever eradicate all conditions and hence extend life indefinitely. There is not a single species I am aware of that has never died. It is basically the definition of life. Species are most viable (strength, can't find the words I'm looking for) around the time they are able to procreate. After that it is downhill. Most of this is of course buried in DNA replication (errors build up over time) and telomere shortening, and a whole bunch of biology that I can't really understand, but suffice to say that something is going to get us someday.