The kids play the game. If they aren't winning, but are getting more and more skilled... it will all pay off when they are hitting 11+. Anything younger is usually the biggest, strongest players win most of the battles. Skill will eventually overcome that.

Note: The vast majority of coaches (if not ALL) want to win games. Some will win at the expense of their weaker players (not play them or play them very little). Others will build the team up — including the weaker players.