It's hard to believe that the principles outlined here weren't at least briefly followed when it's featured on their website too: https://www.valvesoftware.com/en/publications, but I'd be an open to a source which substantiates your claim.
However, non-hierarchical structures are often open to manipulation and land-grabbing (see Tyranny of Structurelessness, etc.) so I am also skeptical that a company may have continued with this practice.
However, non-hierarchical structures are often open to manipulation and land-grabbing (see Tyranny of Structurelessness, etc.) so I am also skeptical that a company may have continued with this practice.