You guys are right. But let's face it, college BB and specifically the March Madness tourney became really popular in 1979. Why then? You had Magic vs Bird? Then you had the Jordan vs Ewing game. Phi Slamma Jamma and the great NC State upset. The Nova upset. All of this happened with named players.
I do think if you have teams with good players staying 3 years or more, gives you better basketball than teams with Steven Adams, or Cam Reddish and others mentioned above.
What is sad, is college basketball (at this point) is a better outlet to build a brand because more people follow and watch than the G League. (Again at this point). But the G League or something could very well develop into like the Canadian JR Hockey league, you can have young talent from Canada, Europe, South America, Africa joining US based talent and make college basketball somewhat irrelevant like college hockey. Sidney Crosby maybe wasn't paid in Juniors, but he had major endorsement contracts already and was a household name.
Basketball can very easily go this route. In fact, even easier, as you need less players. You can still have college BB, but it could really become only interest to those who are alumni of those schools again like college hockey.