If you have a revolution, you’re forming a hierarchy to replace another.
An Anarchist revolution explicitly has no hierarchies, there is no replacement hierarchy.
The concept of anarchism even in its smallest form is unrealistic.
The anarchist collective in Catalonia compromised over 3.5 million people, and how the people operated within it without hierarchies was well documented in Sam Dolgoff's book from 1974, The Anarchist Collectives Workers’ Self-Management in the Spanish Revolution, 1936–1939, along with Gaston Leval's 1975 Collectives in the Spanish revolution, if you'd like to investigate the specifics, such as how they organized transportation, universal healthcare, food production, etc.
Even the Anarchist militias had no top-down hierarchy, they instead adopted a bottom-up fighting force, where a squad of volunteers would elect their squad leader (with the ability for them to immediately recall the elected leader outside of battle if they weren't performing to the satisfaction of the squad). All the squad leaders then elected a commander above them with the same recall ability, and so on up to the general. This is totally unlike any military structure in any centralized state military.
Those revolutions were winning the fight but once the dust settled it would not have continued, anarchy is a lot like a shadow it can really only exist if there is an -archy to be the an- of. You know?
Without trying to offend, this statement shows a clear lack of knowledge on Anarchist political theory. It is a well fleshed out idea that has all of the traits needed for long-term stability. In fact, were Anarchism adopted on a wide scale, it would be very difficult to put that genie back in the bottle, as most people in the world (except the rich or powerful hungry elites) would vastly prefer it over any other societal system tried before.
How do you convince a person who now has access to universal basic housing, food, healthcare, and transportation (where people only need to volunteer about 3 months out of the year to keep those basic needs met for everyone), to instead go back to a system where most give up most of their waking hours to working a job for the benefit of shareholders and CEOs, where most are poor and live at the whims of the rich and powerful, and where whether you potentially live or die is at the whim of Insurance companies, landlords, your boss, etc?