Is anybody willing to attempt to quantify this huge benefit Simmons got by sitting out a year (which doesn't have to do with him just being a year older/stronger/more mature)?
Simmons is averaging 16/8/8 with a PER of 20 after sitting out a year. If he instead stayed another year at LSU and got taken by Philly in 2017, do you really think he's not putting up practically identical numbers? What would Simmons stats be now had he just come out a year later (assuming still on Philly)? That year off really improved his game so much to the point of being unfair?
Sure, he may be putting up better numbers than he would have last year, but that's the difference between being 20 and 21 and Philly being an all around better team this year, not the year off with access to Philly's full staff. Not saying it's not beneficial, but the impact of it is probably so minimal. Guys like Justice Winslow, Dante Exum, Jabari Parker sat out huge portions of their rookie contracts, didn't seem to improve their game when they came back. I'm actually trying to think of an example where a guy missed most or all of a season and actually came back better (hopefully Hayward 2019

), they usually come back the about the same or worse (unless you attribute normal growth and development to that missed year).
So what would Simmons stats be now had he just come out a year later?