If what Tatum is doing since the ~start of the calendar year (again just a rough, arbitrary but logical point for where things turned) is just a stretch of good games we should acknowledge it. Maybe that's what we are seeing but I don't believe so. And again, the data and trend is enough that the onus is on the "not-leveling-up" crowd to show us that he is the same as ever. Or maybe make a case that he is regressing (outside of his 3p% which we all know is below his career norm).
That's the thing with young players. If it is a stretch of good games, we won't know until the good stretch ends. Tatum had some significant room for growth as a playmaker so what we are seeing could very well be real but these "leveling up" posts happen all the time.
I don't know how anyone could say he's regressing (outside of 3p%) though. Maybe prior to December, but players also go on bad stretches of games. It was a 21 game stretch. You are using January as the cut off, so that's a 29 game "good" stretch. Again, maybe it's more than just a good stretch. I'd argue he's been great since Dec 1st, which makes it 41 games (exactly half a season).
TS% by month
.488
.508
.585
.591
.569
.659 (March)
There's also this:
Tatum's first 30 games last year: 35.7 mpg, .433/.364/.877, 24.9 points, 6.9 rebounds, 4.4 assists, 1.3 steals
Tatum's last 34 games last year: 35.8 mpg, .482/.402/.861, 27.8 points, 7.8 rebounds, 4.2 assists, 1.0 steal
Last April: 15 games, 36.3 mpg, .479/.415/.881, .620 TS%, 29.7 points, 9.1 rebounds, 4.5 assists. He had a 50 point, 43 point and 60 point game that month. He then dropped 50 or whatever in the play in game that isn't recorded and another 50 against Brooklyn.
Maybe he's just a 2nd half player.