I didn't ignore that context at all.
Here are Jaylen Brown's 2nd year advanced stats (since he plays less minutes). 54.7 TS% (50.9 2PT, 37.8 3PT, 58.8 FT), 9.3 RB%, 8.0 AST%, 1.6 STL%, 1.0 BLK%, 11.9 TOV% with a USG of 20.6 and a PER of 12.6.
Brown actually doesn't show much improvement in many of those categories from his 1st to 2nd year, which is much diferent then Green who took a pretty big efficiency jump from year 1 to year 2 in pretty much all of those categories (which again is unlike Brown).
There’s a context that you’re ignoring, though. Jaylen went from getting 17 mpg to playing twice that many on a good playoff team. Meanwhile, on both raw numbers and a per possession basis, he improved every single stat except blocks, despite playing against starters and expending energy as an elite defender.
Per 36 Brown year 1
13.8 p, 5.9 r, 1.7 a, 0.9 s, 0.5 b, 1.8 t, 3.8 f - 20 of 78 games started
Per 36 Green year 1
13.4 p, 6.1 r, 1.9 a, 0.7 s, 0.8 b, 2.5 t, 3.2 f - 52 of 80 games started
Per 36 Brown year 2
16.0 p, 6.2 r, 1.8 a, 1.1 s, 0.4 b, 2.0 t, 3.3 f - started every game (54 thus far)
Per 36 Green year 2
16.2 p, 6.5 r, 1.9 a, 1.0 s, 0.4 b, 2.2 t, 2.5 f - started every game (78)
As I've been saying nearly identical stats. They also have nearly identical roles on those teams (at least in year 2). Sure, Boston was a better team than Seattle/Oklahoma City, but the similarities are uncanny from a role, production, etc. stand point.
And don't get me wrong, I'm not suggesting Brown will level off like Green did, but Green wasn't the first or last person to not show much growth (I mean look at old friend KO for another guy that didn't show much growth in his game). Look at Myles Turner from the draft before Brown. Great 2nd year with nice growth from year 1 to year 2, but a major regression this year. Maybe Turner doesn't turn it around and year 2 was his best year. Then again, maybe Brown is like Jimmy Butler, Giannis Antetokounmpo, etc. that show tremendous growth every season.
Obviously only time will tell on which way Brown ends up, but the comparison to Green thus far is pretty spot on given their actual roles and their actual on-court production (not personality wise, but production wise).
Per-36 doesn’t really get to the point, though. Progress isn’t linear; doubling minutes doesn’t double production.
What Jaylen did, going from a 17 mpg role player to an above-average starter and excellent defender, is a huge leap.
And Jeff Green made the same kind of leap. Their per minute production in year 1 was almost identical. Their per minute production in year 2 in basically exactly the same role was almost identical. Green played more as a rookie than Brown, in large part because Green earned his starting spot faster, but Green still saw a pretty nice jump in minutes in his second year, not the 14.4 minutes Brown jumped, but still a solid 8.6 minutes per game increase. Their BPM, VORP, etc. are also pretty close (Green a bit better offensively, Brown a bit better defensively).
You guys can't see the similarities because of what Green ended up becoming, not what he was a 22 year old 2nd year player.
How about this player
20 year old rookie year 32 games played (3 starts) 11.7 mpg, 5.2 p, 1.3 r, 0.6 a, 0.4 s with a TS% of 54.1
21 year old 2nd year 81 games (26 starts) 22.0 mpg, 10.4 p, 2.6 r, 1.0 a, 0.5 s with a TS% of 52.1
Pretty consistent production with an increased role. Making the progression you would expect. Yet for year 3 he switches teams, ends up on 2 teams, plays just 30 games, shoots horribly. Year 4 yet another team 38 games (12 starts), shoots even worse, career low in minutes. out of the league for 2 years before coming back and is now a quality role player for a contender.
I bring up Gerald Green because who knows what will happen in the future. Brown could be Jimmy Butler or the Greek Freak. Or he could be Jeff Green or Kelly Olynyk. Or he could be Myles Turner or Gerald Green. Or any player in between those, but it certainly doesn't mean the comparison to Jeff Green is off base when you would be hard pressed to find two players with on court production and team role that is as closely mirrored as those two.