I disagree with your perspective. Scientists don't need to understand everything about life to make meaningful contributions to our lifespan. This stuff isn't magic - there are sound, repeatable principles at the bottom of everything you mention, and the principles are possibly within our grasp. The technology needed for making these discoveries only gets better with time, never worse.
Look at it this way: crude principles applied at the macro level have extended our lifespan by decades. As scientists get better and better at piecing together the building blocks from the bottom, they'll likely find principles at the micro level that improves our lifespan as well
Look at it this way: crude principles applied at the macro level have extended our lifespan by decades. As scientists get better and better at piecing together the building blocks from the bottom, they'll likely find principles at the micro level that improves our lifespan as well