I don't know the answer, I'm sure someone who is close to players or club can provide facts.Or is it the club?
Lets face it, each time Greenvale kids ( the age group born in 2000 ) have played highest Div ( which has been often ) they have been uncompetitive & thrashed.
So highly likely they want to play U19 Div 1.
You might get the best couple of players who will stay & get some games in seniors. ( if the club is smart it should promise them senior opportunities )