My outside perspective is that Cal sells UK as a pit-stop to the NBA, and that he expects recruits to come in and treat their time at UK as a job where they'll work incredibly hard. I don't know a ton of 18 year olds (and their parents) to whom that message is all that appealing, especially if they're top tier recruits who can be successful anywhere. If anything, it seems like it would appeal to recruits who no one else thinks is a potential 1AD (like Green, Herro, Diallo, Briscoe, etc.), which usually means recruits in the 15 - 50 range. And because Cal is selling those guys on getting to the NBA after one year, a bunch of them are disappointed when that doesn't happen, and they think staying another year at UK isn't what they signed up for.
It's the worst outcome - good (not great) players who want to leave after 1 year no matter what.
Yeah, going on two BILLION dollars includes a lot of those good (not great) players....