So, to give a little bit of perspective about the talent gaps from level to level in hoops....
I played college ball at the NAIA level and started for two years on a top 20 team. I was a top local HS player, but never made all-state. We have a local tournament called the Bass Pro Tournament of Champions that we played in my senior year where 2 local teams play against some of the best HS teams in the country. Every year, a couple of future NBA players are in the tourney. Recently, Darius Garland, Marvin Bagley & Jayson Tatum.
When I played in it, a sophomore Lamar Odom was the MVP. He was KILLING everyone. I mean dunking, driving around, rebounding...it was a man amongst boys and he was only like 16 yrs old. We missed playing them by 3 pts (I missed a 3 at the buzzer), but I got to meet him and he was just a monster compared to my skinny 6'2" white ###.
Fast forward to this season and there is a local kid named Aminu Mohammed. Kid is going to Georgetown and is a top 20 recruit in his class. I've officiated his games 3-4 times over the last few years and he is the best basketball player I've seen up close. He will likely make it to the NBA, but I'm not sure if he'll be good or just a guy. Right now, he is immediately noticeable the second you see him on the court. Most powerful and explosive jumper I've ever seen and he can handle the ball and shoot. I think he is listed at 6'4", but plays like 6'10". He is supposed listed at SG but plays everywhere.
I said all of that to say, that the difference between the NBA players and good HS players is immense. Like a gap as wide as the Grand Canyon. There is simply no comparison and to even make the league today is an amazing feat, not to mention being considered a good NBA player. I'm not sure exactly when that gap became a thing (did Mikan/Cousy/Sharman/Pettit stand out that much?), but I know it has been there since the mid 90's. The NBA requires a special level of freakiness that just is very, very, very rare.