I concur that if the issues of physiology are solved, the layout of culture and psychology would have to change to accommodate, lest quality of life decreases. Just because humans might start living for several more centuries or millenia into the future doesn't mean we can assume there's a hunky-dory post-scarcity wonderland waiting for us there. For one, a longer lifespan means longer time meant working to save for a future of greater needs and wants, to sustain that longer lifespan. Maybe humans would despair that several more centuries of living means several more centuries of work. Alternatively, as how humans experience time changes as a function of how long they live, they may be more willing to work longer if there's a greater diversity of work, and more opportunity for novel experiences and projects that a shorter lifespan couldn't afford.