It's a pretty simple equation if you abstract voting into a competition. One can think of political parties as miniature states themselves. In a world of individuals trying to survive - the ones who survive will not remain individuals. They will form alliances and have power over those who are alone. A small state has little power, but a stateless individual has orders of magnitude less, roundable to zero. Likewise an independent member of a voting body will control the discussion among large parties.
Parties could only be avoided by explicitly outlawing them - and not just by name, but by proscribing specific behaviors which could create de facto parties. Sounds incredibly difficult and would be amazing to watch attempted.