I understand what you're saying but you're missing my point. Jahlil isn't going to the NBA because of K. Towns isn't going to the NBA because of Cal. They could've gotten there had they never played for them. I'm not trying to downplay any role they have in helping them.
My original point was regarding the comments Cal said that if I were a top player, I wouldn't really want someone who coached me; or is going to coach me for a year, saying he got me to the NBA. If I'm a top player going to the NBA regardless of who coaches me, I'd want their priority to be winning. If I know I'm only going to college for one year, I want something to commemorate my time there, which Jah, Justice, and Tyus have certainly done.
Not all 5 stars or burger boys are Jah or Towns level. Not even close. If you want to take away Wall, Cousins, Davis, Towns, Okafor, Kyrie, Ingram type players, that's fine.
There were also Rivers/MKG types who were uber elite recruits but had some major hole in terms of NBA desirability, and still got picked high (2 for MKG, 10 for Rivers), you can decide whether to factor them in or not.
But once we're talking about guys outside the top 5 and especially outside the top 10, it's a vastly different story.
Go look at the average rate of landing a guaranteed contract in the NBA for all rivals 5 stars vs just the percent who play for Cal or K (if you like, break it up into top 5 recruit, 5-15, 15-25 to control variables), and you'll see that it's absolutely, without question not all the same.
If you think that some vast majority of elite HS players end up with a contract in the league, you're just not paying attention to the ones who land at lesser schools - and that's half the point here.
With Cal, any time I can remember that he "split commitments" on two kids where he wanted both equally and who were ranked within 5 of each other, well just think about their career paths:
between Cj Leslie and Terrence Jones (top 15, long forwards with outstanding athleticism/potential),
Renardo Sidney and Demarcus Cousins (all world HS talents, not athletic but with massive hype, skillsets, and attitude problems),
Josh Selby and Brandon Knight (elite 6'2/6'3 HS guards with awkward combo projections for the league, Selby having far more athleticism),
James Blackmon Jr and Devin Booker (low end 5 star 6'4/6'5 guards, not particularly athletic, known as shooters).
I'm sure you can do the same with K.
I know, I know, anecdotal evidence is the worst, but do your own homework and go down the line with 5 star kids (particularly non top 5) who went to places besides UK and Duke, and compare their typical results. I think you'll be surprised.
It's not just about development, either, certainly - exposure, being able to play with better teammates, excellent training facilities, hype from postseason success, I'm sure all play roles, however trivial.