When I started in this biz in 2006/7 I threw out the $35 min charge. That flat out did not fly here...most of the time.
Let's put it this way...if your prices have to drop to meet market pressure you flat out have to have market density to float the boat.
Square foot flat rate prices is something I refuse to dabble with. Many smaller lawns are obstacle courses and burn up much time zigging and zagging and extra trimming.