That's a combination of a few things.
First, you live and learn. Things evolve. He dominated the hot minute of CBB history when NBA age rule, OAD, ranking services, elite AAU circuits all kind of converged and took off.
All that cooled down as it really only applied to a handful of programs. The pendulum kind of swung back to traditional program building.
Secondly, NIL player empowerment. Players outside of top 15-20ish are going to have incentive to stick around now. I know it's not first round money, but it doesn't have to be. Lifestyle of an athlete at a top 30 P5 is a better than slugging it in the G league and/or most overseas leagues. Especially now that they're making some money.
Cal isn't going to be able to push the projects out like he has been. The "go get your money...eat...feed the fam..." etc pitch is going to be a tougher sell. The later first, second round, and free agent sign guys are going to be like "whoa hold up coach, I'm good here. Cowboy, Chicken, and Walmart money is good. I get carted around on a golf cart wherever I want to go. There are personal chefs, massage therapists...the fam made it 18 years without the league they can hang on another couple"
Third, the NBA has evolved. I don't know if anyone has noticed, but top CBB talent is getting passed up for overseas projects. The spots for guys to jump early are dwindling.