Things will change 20-30years down the road significantly. Replenishment of stem cell pools (the rejuvenation of their "niches", etc..), ability to "code" transcription factors (so instead of using GH, people will use viruses or other stuff to get tha mRNA into their body to make it produce certain proteins at the levels of young organism), tweaking of DNA chromatin structures (so to literally "turn back the clock" on a cellular level), and many more, which aren't even discovered curently (but progress is astouning).
It's nothing more but a very specific cellular processes that go wrong over time, due to the lack of selective pressure over the generations after a certain age (reproductive peak), it starts to diminish gradually so the "code" ceases to adapt and stay in a phenotype, called "youth".
Don't want to upset you guys, but you/we may be amongst the last generations who'll die from an old age (given the current pace of progress at understanding of what's really happening "under the hood"). Sounds bold and maybe even ridiculous, but that's an inevitable future, and the goal of an "evolution" of any given species (we, humans, have reached the point of evolution where we start "tweaking" our own evolution consciously, to speed it up.)
