It doesn't seem like it's about strength, necessarily. Ordinary voters just can't keep track of more than a few factions. (And forget keeping track of the individual issues).

Where things manage to be non-partisan, it's because there's a strong and extensive network of local power brokers that people will listen to, like pastors or elders. Failing that, parties emerge over and over again to present a brand, and actual issue-by-issue decisions happen inside.