Yeah, we'll definitely want a "dementia moonshot", or a few, before we attempt to create a generation of centenarians. However, cancer incidence climbs terrifyingly rapidly when people reach their 60s - long before we are ready to give up on them. A successful cancer moonshot (and the Nixon one, by the way, was quite successful) will let millions of people enjoy many good years with their loved ones; not to mention that it would also save many young people from dying of cancer, although that's a much smaller share of cancer patients.