Aging is programmed: because the Hayflick Limit (number of times a cell is allowed to divide) is part of the bodies defences against cancer.
Telomere shortening means that cells that replicate too much hit the replication limit, trigger p53, and self-destruct via apoptosis before acquiring enough mutations to become an cancerous tumour.
Telomere shortening protects young organisms from early-onset cancers, but it causes tissue aging and degeneration later in life.
It's an evolutionary balance between cancer and health.
https://wikipedia.org/wiki/Antagonistic_pleiotropy_hypothesi...I've long been a fan of this view (though i do think some aging is also essentially entropy).
Natural selection favors organisms with a lifecycle time that is optimized and not random. Some organisms will benefit from shorter lifecycle times, e.g. to adapt faster. Others will benefit from a longer one, e.g. when fitness increases with experience. At some point, if your organism is no longer contributing to the future success of the genes (not necessarily by mating, you could be an awesome orca grandma, imparting wisdom), you might as well get it our of the way. A striking example is how some octopus species waste away after giving birth.
So it shouldn't be a surprise that there is a fitness advantage to controlling this process.
That said, if we altered this program to increase lifespan, I'd expect we'd start to run into more entropy-driven aging.