I think we could get the average life expectancy up to 100 if we did a better job of all the preventative things:
* Prevent airborne disease by having all indoor spaces getting 50 air changes/filters per hour.
* Prevent waterborne disease by having all tap water RO treated in homes, and by heating all shit up to boiling point before it leaves toilets.
* Large scale animal and human trials of every chemical used in daily life to find those things like a pacifier which gives you cancer 60 years later. It is far better to do an 'unethical' trial of a chemical than the current system of just putting it in all products and going bankrupt later.
* Prevent spread of other diseases like the common cold with daily covid-like lateral flow tests for everyone, with the government bringing you food and paying you to stay home if infected with any spreadable disease.
* Work on many more vaccines and give them out for free to the whole world to eliminate more diseases like we did with smallpox (that vaccine has saved around 800 million lives).
* Dramatically reduced effort on individual treatment (cancer, care homes, etc) by putting a 200% tax on healthcare, and funnelling that money into preventative things so the next generation doesn't get the health issues at all.