Ironically the Bolshevik revolution didn't really start out this way. The Bolsheviks advocated for a strict disciplined party model - if you've ever read what Lenin wrote of the Left-communists and Anarchists, it was clear that he was very much not mindlessly "against" structure. Of course, this would all eventually be liquidated by Stalin and Mao.

"Flat" organizations rarely seek to deliberately create cabals and power cliques - they do inevitably occur, sure, but the call for flatness usually comes as a result of you not getting what you really want out of the system. Ulterior motives are not really at play; rather it is just a case of organic collapse.