I am in favor of curing disease. However, as for life extension, I am opposed as long as we continue doing what we have been doing. Twenty years - dependence on others, forty years - dependence on one's self, twenty to forty years - dependence on others, death. This is the average cycle. I am not forgetting the exceptions. Society has a hard enough time now to house and feed the elderly; what will happen when people live to be on average 125 or 150 years? The welfare state is on the collapse across the world, and it was this state that helped to improve the lives of the elderly. And there's age discrimination, which starts at around age 40 and escalates from there. If there is no welfare state, and the elderly aren't able to get meaningful employment, aren't we, as a society, prolonging the inevitable more than we should and increasing needlessly the suffering of others for selfish reasons?
We have more than enough resources and technology to provide 3x higher living standard for each individual on the planet compared to what the richest person presently enjoys.
The trick however is that you are looking at things from a monetary point of view.
You don't ask (do we have the ability to provide for everyone in such a manner).
The answer is yes.
Give each person individually 93 square meters, and you'd only take up the entire state of Texas (without building vertically).
We can feed everyone by making fully automated vertical farms (employing hydroponics, aquaponics and aeroponics) that also produce both water (atmospheric water processors) and power (photovoltaics, geothermal, wind, pizoelectric - essentially, DESIGN the structures to be both energy efficient and produce resources from the get go) - 1 such farm on 1 acre of land (the size of a football field) and 44 stories high can produce enough food to feed 613 000 people (10 different vegetables per person daily).
And these are things that were doable decades ago.
Energy is not a problem.
Geothermal alone can provide enough power and heat for the next 4000 years at present levels of usage.
Solar would require less than 1% of Earth's land mass.
There's also Space based Solar power (24/7 energy production).
Instead of extracting resources from the planet, we should be using all those millions of tonnes of landfills for production of superior synthetic materials which we can make in abundance.
As for people claiming that the population will continue to rise...
The only reason some countries have a high birth rate is due to lack of education.
Countries with educated individuals, security of life and access to quality medical care are below replacement birthing rates.
I find it amusing how people jump to the notion of 'cost' factor and completely invalidate the things we actually need to require a sustainable society (resources and technology - both of which we have had and could have made in abundance since the late 19th century).
This idiocy that longer life spans create more strain is only accurate for the present socio-economic system (which is unsustainable anyway and is eating itself like a cancer).