Yeah, I’m similarly puzzled by this statement, along with the overall fascination with Luke given his weaknesses and lack of high-level abilities in any one area.
Further, there are going to be matchups where Kornet in the double big lineup is just unplayable and you need to go smaller with Stevens or Oshae along with a traditional big. Like, while I prefer Queta over Kornet, I understand why Joe trusts Kornet more, but virtually cutting out Stevens and Oshae except for injuries and SEGABABAS I think is a bad approach when they’re very versatile defenders that are better suited in some matchups.
One thing I wish Luke would do is to get back to being an outside threat. He came into the league as a big man shooter, but has seemingly completely cut that out of his game. If he got back some of that ability he’d be more useful offensively and could continue the maximal spacing our team provides from all our rotation players, except him.
The way I read it is that Joe knows who his top 9 is - he knows his top 5, Al is the first guy off the bench as a big, then PP and Hauser as a ball handler and wing, then Luke as the second big. But as we all know Joe is an analytics guy...he lives and breathes by analytics. He answered a question in a presser once by saying that teams that led after 3 quarters have a 67.4% chance of winning the game (I might have got that number wrong but the gist is how those analytics drive him). It's why he has this insistence that his team "shoot more 3s" - I think there are stats out there that say that if you shoot x more 3s than the opposition, even if you shoot at a y% lower clip, you have a z% chance of winning. I have no proof of this and may be unfairly maligning him but that's my feeling about his style.
So for matchups I think he is much less likely to just roll the dice and try a sub "for the heck of it" - somewhere someone from their nerds department has all the stats on matchups, and which player has the best matchup against the other teams, and if in those cases it is someone other than Luke that's when we get those "surprise" matchups where he pulls out Brissett or Stevens or someone and then his decision either gets vindicated or repudiated, which determines whether he rolls with it again or not.
I don't think it's cast in stone, just that this is the 9 that he's decided will be his default rotation, and the only way it changes is due to injury, fatigue, load management or as a horses-for-courses thing based on matchups.