I think the biggest detterrent to the California PAC-10 schools is budgetary. CAL and UCLA both are part of the huge budget crunch going on in the system there. Non-revenue sports are definitely hit. TV money is huge for basketball and football, but the crowds and, in the case of UCLA, the absense of an on-campus football stadium must hurt (this is true for USC as well). UA and ASU have had flashes of sprinting genius, as has USC, who is a contender nationally on both the men's and women's side this year, albeit without as deep a team as many SEC programs.
Stanford is obviously doing just fine going the distance route, and UO, Washington, and WSU must go the distance/field route for the most part due to weather and in-state talent pools.
If we really want to talk about an under-achieving conference (perceptually, anyway), let's discuss ACC men or Big 10.