Eh. I worked at a reasonably holacratic/flat organization (a high-profile agile consultancy, actually), and when I say it was flat, I didn't know who my boss was, or who to give notice to when I quit. It was honestly very flat, and in no sense did this mean "secretly rich white guys ran the show." It did lead to a bit more cliqueyness than might otherwise have been desired.

I think that a holacracy, like most things dealing with human beings and their behavior, is dependent on the specific human beings in question with regard to whether or not it will succeed.

On a slightly meta level, it is interesting why the startup/development culture seems to flock to articles like this, saying "such-and-such thing can never work as a solution to people problems because it didn't work here" - we see this crop up on HN constantly, pro- and anti-, with things like working from home, pair programming, etc. Maybe it's too much to ask that we say "different things work for different groups of people"?