I've heard from multiple sources -- people I have found reliable in the past, who either are or know players' parents, etc. -- for most of the season, but especially around the bye week (which is about when it became about 100% clear the Big 12 invite, always low-probability, was exceedingly unlikely), that if WSU wasn't playing in P5 next year, a ton of guys were looking to transfer. I don't have specific numbers but the adjectives I have heard have been, e.g., "tons" or "a shitload." I wouldn't be surprised if it's 30, as you surmise, or even more. Just about everyone on the roster thinks he's a P5 player, either currently or with the talent to develop into one (in the case of freshmen, etc.), regardless of how accurate that may be objectively.