One practical problem is that rollout of anti-senescence will not be evenly distributed. In the early days of its availability, the oligarchs will use it to accelerate the growing chasm between the haves and have-nots, aiming to make their advantage permanent by pulling up the ladder behind them.

It's not just about power structure: if you never known anything but pharaohs and pyramids your whole life, it's extremely hard to imagine anything else. The youth is programmed to revolt against the old ideas to test them, no youth no revolt.

I also you think both your assumption and the reasoning behind it are wrong. Humanity as a whole is the opposite of apathetic, it's boiling with life. There are occasional pockets of apathy here and there, but they never last long.

And the reason why people on average are active and risk-taking is because their life is worth nothing. You lose your life no matter what you do, so you can as well do something good. And if you want to see change in your lifetime you better hurry up.

No one would risk their precious eternal lives if aging is gone. And if you want change you can safely wait forever without taking risks, maybe a meteor will fall in 10000 years and change things — who knows!