Not totally true. There's a whole suite of social problems stemming from having a large elderly population in poor health. Insufficient pensions, how to pay for healthcare, staffing in caring professions. If 'studying the science of ageing' translates into 'keep older people healthier for longer', then those problems may be mitigated somewhat.

Also, scientific advances can make treaments cheaper. E.g. modifying bacteria to produce insulin is cheaper than extracting it from pigs.