This new program that the NBA has will likely give those that want it the chance to skip college and go to the G-League, get pro coaching and salary before being eligible for the NBA. Between that and overseas (particularly Australia), we could see a dozen or so top players skimmed off every year.
That means there probably won't be very many true "difference makers" coming into the college game each year. You don't get Andrew Wiggins, but you do get Wayne Selden. You probably won't see much clustering of talent, either. Without truly elite guys to build around, the complimentary guys won't have much reason to flock to the same school. I think that's what we are seeing.
With the drop off in talent, I would also expect more guys to stay for two years, rather than jump after one. The guys that can jump after one probably never show up. The NBA game and college game are just so much different from a pace and structure perspective.
And if the NCAA doesn't figure this out soon, they will be a relic of the past, too.