No, we want to argue that more good players leave early. As I mentioned in my last post, Okafor and Gordon won a championship as juniors and then went #2 and #3 in the draft. That is unheard of over the last decade, it simply doesn't happen.
College teams that were a mix of experience + high-level lottery talent are a thing of the past.
The depth of talent is better but the top-end talent/teams is worse.
You are talking about a handful of players leaving maybe a year earlier than they did a generation ago. I don't see the seismic impact.
I would also point out that given the huge number of total busts in more recent NBA drafts, college sports may not be missing much with some of these players leaving early or never showing up on a college campus.
Look at 2016, the most recent draft for which we can make a fair assessment since players have had enough time to develop if they were going to. Did college basketball lose much by not having Thon Maker or Jakob Poeltl not play more games? How about Malachi Richardson?
Ben Simmons would have left after 1 year no matter what decade he played in. Jamal Murray and Jaylen Brown may have stayed another year if they had played in the 90's. Siakum and Sabonis would have left after their sophomore year if that draft was held in 1996. The rookie of the year of that draft, Malcolm Brogdon, played 4 years of college.
Out of the 2017 draft, maybe Markkanen or Fultz stay another year if they played in the 90's.
In terms of depth, other players replaced the stars that left a year earlier than they would have historically. Duke, Kansas and Kentucky survived the departure of Tatum, Jackson and Fox. There would have been a domino effect, but here is where we get into the impact of better overall talent in the college game.
It is also worth noting that Gordon and Okafor were not McDonald's AA's and both took an extra year to develop into lottery picks. They are not good examples of players that would have left early if they played today.