KJ/lottery picks: It makes no sense to come back. 4M is equivalent to the 13th pick in the draft. But if you stay in college you could also be losing out on $ by not be able to hit your rookie extension until a year later (if you are a hit in the league. and every lottery pick thinks they are gonna get extended). Or you could get hurt, or play poorly, or stay the same and be another year older. All bad. You aren't going to jump Dybantsa and the Boozer into the top 3-5 picks. The theoretical number is too high it would hamstring the whole operation.
JT Toppin/Fringe 1st rounders: 4M becomes a lot more enticing if you are projected at pick 30 (2M/year is best case scenario) and you realize getting extended is a bit of a longshot. So you can take the 4M this year, get drafted at the 2M/year next year and you may actually be extending your high earning period.
Will Riley/mid to late firsts: 20th spot earns 2.8M. and GMs dont like giving up on top 20 selections they make for job preservation purposes so your extension odds also increase.... And his stock could take a hit because he will be over 20 years old at the 2026 draft (Ancient for NBA GMs). Probably too much downside risk for Will IMO. Now if he slides into the pick 30-35 range.... maybe there is a # that makes sense in the 4M range like toppin?
TLDR: If you are a first round lock you go -- KJ is and it seems like Will is trending there. Dame Sarr your table is ready.