Taxi Rates

I suspect that the high price for Troncones is because the driver taking you there isn't allowed to pick up a fare for the trip back to Zihua; thus, they charge you for their trip back with no fare.

I agree. That would factor in. But they can pick up fares once they leave Troncones. I have always considered the Troncones taxis to be one of the more aggressive taxi unions in our region, and because they play dirty (and hypocritically), they ruin a good thing for everyone including themselves because I certainly won't recommend or use their services, and I know I'm not alone.