"If only 10% of the people (as an example) actually voted for the "rulers" then why would the other 90% obey whatever the rulers decree?"
Three answers... weapons, prisons, and belief in their authority. I'm not convinced that voting is why people believe in their authority so much as the fact that they can and will come after you in the right circumstances. There's a huge difference in 90% of people not voting due to apathy vs. 90% of people not voting due to lack of belief in authority.
RE: A mathematical explanation how voting third party in 2016 is the only vote that counts