Hard to say. Bishop tourism is heavily summer oriented: hiking, fishing, Mule Days Memorial weekend, a rodeo Labor Day weekend.
The Intrawest years were 1998-2006 and the plan then was to make Mammoth a true national destination. Access remains the biggest deterrent if you poll skiers from the eastern 2/3 of the country, and the highly unreliable Mammoth airport only served from west coast cities (thus 2 plane changes for many easterners) hasn't changed that issue much.
Interesting story in yesterday's (Sunday) NY Times travel section on the overcrowding problems at many ski areas because of the popularity of the Epic and Ikon passes.