NBA mock draft 23 out of 30 are freshman or sophomore...

[Xavier2005]

One of the major 2019 NBA mock drafts has 23 out of the top 30 in the first round as a freshman or sophomore coming out of universities. The other 7 out of 30 are either from a foreign country(3) or junior(1) or a senior(3). If a college player stays for 3 or 4 years at a university playing basketball, he has little to no chance of being drafted in the first round...because the players best suited for the NBA come out early.

[olsingledigit]

What I surmise is that these four year players are not missing an opportunity because they stayed four years but they simply were not as talented as those freshmen and sophomores who were drafted.