Before I write this, I want to say that I am completely for changing the way the professional and semi-pro leagues are run to match that of the rest of the world.
The United States may be different from other countries in the way that we have standings, determine outcomes, etc., but think about this. In high school sports in this country, especially in the playoffs, the crowd and the players show up to determine a winner on that night. I don't think that after years and years of this method, many people would be keen to change the playoff system to have a replay (like the FA Cup) at the opponent (who has a worse seed)'s stadium. If you changed the way we end games in high school soccer, you would have to completely re-do the entire way that soccer is played in this state and at the high school level I do not think that that is a good idea at all.