After winning the league regular season for almost 2 decades, the Zags are getting the big boys to Spokane. Don't know if 2 for 1s or straight home and home but it's happening. And the top 3 you identified in the WCC, private faith based universities, as are all their members. BYU plays FBS football, St Mary's FCS Pioneer League (no scholarships).
Bottom line, it took the Zags a generation to get where they are at...and some in the national media still treat them as a novelty. Happy for them, twenty years in the making.
St. Mary's dropped football after the 2003 season. BYU (should be in the Mountain West) and San Diego (FCS Pioneer League) are only football schools in WCC.