Actually it does matter. He could possibly lose millions of dollars by chosing a school other than UK. Cauley and Booker were lottery picks at UK, but would've been second rounders if they had gone elsewhere. The Kentucky affect really does exsist.
How do you know that Cauley-Stein and Booker would have been 2nd rounders had they gone elsewhere? You have absolutely no proof of that.
If some of these recruits chose other schools, it's also likely that they may stick around college a little longer. For some of those guys, it would actually be better for them in the long run to stay in college longer. At UK it's like a conveyor belt, and basically everyone is expected to be gone after 1 or 2 years. That's not how UK players should feel, and this fan base should not look at the team as needing to be a conveyor-belt like team.
Devin Booker may not have been the 14th pick or whatever after his freshman year had he gone to another school, but it may end up being the case that it would have been better for his long-term future to go to another school that doesn't push players out the door and act like they develop everyone under the sun into a pro after 1 year. And Booker may well turn out fine in the NBA, very good player, but he is in no way, shape or form, any kind of "special" SG talent.
Dakari Johnson is a guy who should have absolutely played 3 or 4 years of college, and he likely would have at another school. It's like UK wants to lump every 5-star player together and act like they can all be 1-and-dones, when that's stupid. The only types of players that should truly be 1-and-dones are special talents, like Wall, Cousins, Davis, Towns. Noel was arguably part of that group but I'd put him a tad notch below those guys.
Special talents will succeed regardless. The "very good" talents may or may not make it depending on what situation they go into in the NBA. These guys would largely do themselves well to stay in school a year or two longer. Like Eric Bledsoe has turned out fine for himself, but Marquis Teague has lost his way.