Unfortunately, you combine more recent success, better weather and superior facilities at a bunch of the top Pac 10 teams,(nevermind ASU/U of A putting less effort into in state recruiting as of late) and it's not surprising that so many kids do decided to go out of state.
You'd have to think that playing in front of family/friends and supporting your state is definitely less of a priority in AZ compared to many other major conference teams. Hopefully that changes at some point, but like getting locals to root for the home team, I assume it'll just take time.
Facilities aren't the issue. It's all about community pride, or lack of it. Very few are
proud of living in Arizona, and in the lifetime of the current recruits, the in-state schools have done very little to instill it.
But let's be honest: When both schools have been at their best in the Pac era, the rosters have been about 2/3rds Californians. We obsess over in-state kids because it's a pride issue, and this year is very special with so many quality recruits. But if either school is going to stand up and be consistently good, they're going to win in SoCal, keep a couple of the game-changers in Arizona, and cherry pick in places like Texas and Colorado.
I look at the best players on ASU's all-time list and notice where they're from:
Curley Culp: Yuma
John Jefferson: Dallas
Eric Allen: LA
Danny White: Mesa
Jake Plummer: Idaho
Mike Haynes: LA
Randal McDaniel: Avondale
Todd Heap: Mesa
Pat Tillman: San Jose
Terrell Suggs: Chandler (by way of Minneapolis)
Ron Pritchard: Bay Area (Antioch, IIRC)
Will Sutton: LA
David Fulcher: LA
Dan Saleaumua: San Diego
The Malone brothers: Eloy, by way of Texas
Ben Hawkins: New Jersey
Bobby Mulgado: Pennsylvania
Jim Jeffcoat: New Jersey
Zach Miller: Mesa
John Mistler: Missouri
JR Redmond: LA
Woody Green: Portland
Todd Kalis: Minnesota
I could go on, but the local guys on that list don't even make up half the list. Some of ASU's very best players have been local, but the overall mix has never been some referendum on in-state recruiting.