It's so weird then. I mean, Dallas has two studs, but Boston is defending EVERYONE instead of focusing on the two studs. Meanwhile, Boston has a bunch of guys that can score a ton, and instead of guarding them all, Dallas is throwing waves of defenders at just one guy (Tatum)?
It's not weird, it's personnel. DAL has had to play this way because if they didn't, teams would be getting layup after dunk after layup. So DAL has had to make things difficult at the rim and their entire defense has been premised on rim protection (I posted the stats on FG% on drives by DAL opponents throughout the playoffs). DAL has been willing to give up 3Ps to other teams because they have been playing teams like RWB (23.5% from 3P), Amir Coffey (27.3% from 3P in 112 minutes), Zubac (no 3P), Giddy, Chet, and Aaron Wiggins (18.8%, 22.2%, and 28.6% from 3P, respectively), and NAW, Anderson, and KAT (18.8%, 28.6%, and 24.2% from 3P).
At the end of the day, DAL basically gambled that the FG% of the shots they were willing to give up would be lower than the FG% of the shots Luka was able to generate.
But BOS turns this math on its head by getting guys into rotation and getting great shots - rim looks or open 3Ps and daring Luka to try to match that for 48 minutes.
As HRB has said, teams get to the Finals based on systems they've incorporated over the course of the year. It is unlikely to me that DAL could start staying at home on shooters and not help at the rim. But even if they did that, the shots JT and JB would generate against Luka and Kryie would be wildly better than shots Luka and Kryie are generating against our 4 potential all-defense guards and wings.
One corollary question that you didn't raise but is much more interesting to me - why didn't Chris Finch or Daignault basically do to DAL what BOS is? I mean both of those teams could hide their big guys on a non-shooter, play Luka 1 on 1, take away the corner 3Ps and the lobs (although OKC being so small probably would have a harder time doing that). Both of those teams lost because they sold out trying to stop Luka.
It will be interesting if BOS changes the way the entire league plays DAL next year.