Why do you say anarchy is fragmented? I don't know if it has been tried but maybe because we didn't have the technology until now.
Anarchy lacks the ability to organize because of the lack of central authority.
You can have authority in anarchy (doesn't have to be central). The only difference is it's not coercive, people can choose to participate or not, and let's say they have to pay to participate. Why wouldn't that scale?
Have you ever heard of big companies?
You mean companies? With CEOs? That would be the central authority.