Folksonomies pick options everyone finds reasonable, not ones that everyone thinks are best.

A folksonomy allows the emergent, bottom up judgment of the swarm of users to decide which options get the most attention.

One of the reasons it works is preferential attachment: the options that are already popular are more likely to be shown as options to other people and thus get even more popular.

The test is not "Do you prefer A or B" it's, "Do you prefer A, with X votes, or do you prefer B, with 100X votes".

As B gets more momentum, the power of its momentum dominates the preference.

It could be that A and B started off equivalent, but B got a head start that then compounding into a dominating advantage.

Folksonomies don't find the optimal ontology, they find a known-to-be-viable ontology.