It is, in short, a degenerative process marked by the failure to perfectly maintain instruction sets for the creation and maintenance of structures that allowed for survival.
Reading that back it almost sounds political.
I don't think there is a scientific consensus on this particular mechanism as a root of aging. There is a lot of stuff happening along like epigenetic aging, accumulation of various toxins and seemingly pre-programmed atrophy of immune system in mammals.
The only de-aging experiment that demonstrated some positive results in humans didn't touch genes at all. It was the TRIIM and TRIIM-X trial which attempted to rejuvenate the thymus and thus reinvigorate immunity. The subjects exhibit a lot of changes consistent with being a bit younger (a few years).
Immune atrophy and toxic accumulation I would read as being the terminal effects of decreased functionality as a result of error accumulation, no?
https://www.lifespan.io/topic/why-we-age/
But there has been recent talk about adding five more:
https://www.lifespan.io/news/researchers-propose-five-new-ha...
Aging is complicated. Stuff like extracellular cross-linking of collagen through glycation cannot be reduced to genetic/epigenetic changes, and yet is obviously a huge problem for aged organisms.