You're making the mistake of assuming evolution is progress; that's not how it works. Evolution is adaption to the current environment, that could be progress

You're making the mistake of assuming evolution is progress; that's not how it works. Evolution is adaption to the current environment, that could be progress or devolving, whatever works better. Older genes are not inferior. Secondly, evolution works across great timescales, doubling or tripling lifetimes won't stop evolution. There is no evolution problem. Thirdly, if people could live indefinitely, there would still not be an evolution problem, there'd be a population and resource problem, which would change the environment thus accelerating evolution by selecting those who could survive on fewer resources or those capable of obtaining resources.