I agree with you, college is to learn how to think, develop an intellect and network. But the end game, the ultimate goal, is to earn a degree that will allow you to obtain the job you want. That's why there are majors and curriculum. I don't know why people choose ND because I didn't have that option, but I assume it is for the different experience and the networking. There's value and both of those things, and there's a value for having a degree that says it's from ND. The value of those things are different for everyone, which is why the cost of attending ND/private school may not be worth it for many people.
Back to the one and done players, I think they experience these three things at UK as well. I also think UK provides a unique experience and networking opportunity than other schools, which is why the they get more one and done players than anybody else.