Just from what I see, keep in mind, I started playing in 1980.....it was there.....you had pillars of the hockey community, Pickwick, Culver, Paramount, Norwalk, the old Thousand Oaks barn, Van Nuys barn, West Covina before they closed, Pasadena,the old Costa Mesa rinks the old Ontario barn, etc, there are probably 3-4 that I am missing cuz old age sucks....Gretzky came along, so you had that craze, West Valley, etc, then Anaheim gets a team, so Lakewood, Anaheim, and probably another 4-5 other rinks open in and around the IEL, OC, etc....you had the Jr. Kings, and the Jr. Ducks, and you had the very very very beginnings of the WSHL Junior B is what is started out as....
Now.....I believe the WSHL is Junior A, and a feeder system into the NAHL etc, but you have sponsored high school leagues, the registration for the area is sky high, you have a ton more grass roots options than you did....even after Gretzky.....
I don't have concrete numbers.....but I was there before Gretzky, during Gretzky, after Gretzky.....and the options that a player has now playing in Southern California, is a helluva lot better way back when.......and I don't know if it was winning the SC that did that.....but I am sure if I dug around, I could find the registration #s for 2010, 2011, and compare them to 2014, 2015 and you will see a significant jump....