Anarchism

I'm taller than you. I leave some important stuff up on a high shelf. You have to ask me for the stuff

This is definitely not the type of hierarchy anarchism or marxism seek to dismantle. Natural formations of 'power' that come from biological differences arent the ones we're concerned with, but the larger structures built around them are. If you're taller than me and can reach things I cant, we can structure our organization so that either I can reach it wothout you (stairs) or so that I dont need whatever those things are (a job that doesnt require those things). What anarchism definitely isnt going to do is either make me taller or you shorter.

And oh yes gerontocracy absolutely can and does assert itself without a state

Same deal. Being older and less able is a natural 'hierarchy', but what concerns us isnt the handicaps that naturally arise but the structures we build around them. If we distribute food and resources according to ability but make no consideration for less-abled people, thats the problem we are solving for, not the eradication of handicaps entirely.

Maybe you know this and it'll sound like I'm being patronizing, but ultimately both anarchism and marxism seek to arrive at the same place of 'to each according to need, from each according to ability', and that will require structures that replace the things states do with more involved community organizations.