Resource accumulation always leads to power, and that seems to be a fundamental weakness of anarchy.

You're right, as long as greedy people and a means of hoarding resources exists (e.g. money) people will be able to accumulate power. This is why anarchy is often shorthand for "anarcho-communism" which is moneyless and removes a malicious person's ability to pay others to back them up leaving them vulnerable to self-defense (which is now not prevented by the state) by the communities they are trying to exploit.

This would go along of course with the end of capitalism which is what puts people in a position where risking their lives for money makes sense in the first place.

Two ways to deal with it

1. Eliminate means of resource accumulation (i.e. money) -- with communism

2. Keep in check the tiny number of individuals with the dark-triad traits that cause them to want to accumulate power -- with self-defense.

This all needs to happen with major changes in culture and could not come from a simple revolution.