I think it's a little more complicated than one metric can show. Davis doesn't have much in the way of a post repertoire - he's all putbacks, alley-oops, and particularly spin lobs out of postups. Any pass that moves him away from the basket is no good, because he'll face up and shoot jumpers, and apparently those are exactly the kind of passes that Schroeder sent his way from the fans who have watched more than I have.
While it was fairly obvious that they didn't have any chemistry in the handful of Laker games I watched last season: I've read from some more die-hard lakers fans that Davis got one successful lob from Schroeder on a grand total of two attempts. That's not the best way to use your best player.
It's no coincidence that Davis's two best seasons in the league have come when he was playing with Rondo, who is a guy that is absolutely going to get you the ball in the best position for you to score.
Now, is the swap to the greater detriment of their team? Maybe. I think the bigger problem is that Davis continues to want to play like a wing when he clearly isn't at his best when doing so.
I hope that the Lakers are worse with Rondo because I want the Lakers to lose basketball games, but I see no reason to suspect Davis will be worse with Rondo, and there are many worse things than having your backup point guard complement your best player.
To be fair he's still one of the league's better post scorers even with a less than ideal moveset there:
https://youtu.be/bDrxk64UTPU?t=271
Yeah I certainly don't want to sound like he's useless in the post (he's clearly not), just that that's not where he's at his best.
A few seconds later in the video (which is a great breakdown) the narrator says "still, those little jumpers aren't super accurate, and per Synergy his points per possessions on these post ups is 21st among the high-volume players, making him good, but not deadly. I view it as a value add to his incredible diversity and massive off-ball value."
