An alternative way of looking at it is that societies do better when they make full use of their resources. Saudi Arabia has long been criticised (by lots of people, but particularly relevant here) by economists for the way they keep women out of the labour pool. They are making themselves uncompetitive by this.

It's the same for North Korea - who are getting rid of their most interesting voices for change into hell holes.

So an economic argument would be that we are currently running the years 67+ as unproductive, and the first society to change that will do better than the others. It's also possible that this is the first time in history it would be safe to allow life extension in a lot of countries due to the falling birthrate at the same time.

Oh, and immortality doesn't mean living forever. I read somewhere that even if we could extend lifespan, actuarial tables show that on average people would live to about 700 before dying of accidents.

> You could make the case that you continue to work past 65, but in what field. How many 85 year olds are in fields they could stay relevant in?

I think this depends on whether the brain can be made young, too.