I think this is a pretty nuanced subject. Doncic has been AWFUL on D this series, as you say. This compilation is from before the game and he was even worse in this game. .He can barely move out there. We all know he's not the fastest guy around but he's in slow motion these playoffs. Whatever percentage you want to put it at is fine but he's seriously compromised. He legit can't even move for loose balls that are right by him and he's saving what he has for offense and abandoning defense. He needs to get a lot better on defense but I haven't seen him move like this on either end of the court in my years watching him.
Credit to the Celtics, they are loaded with good perimeter defenders but he's nowhere near healthy. He has a bum knee, a bum, ankle, and he's getting shots for his chest injury.
I think all these things are true
1) He's banged up. Definitely.
2) But he's always been incredibly bad at defense. I was ragging on him for it and saying Tatum's defense was comparatively more better over Luka's D than Luka's offense is better than Tatum's O 4 years ago.
3) It's hard for him to hold up in the playoffs without getting hurt because he has such a big usage and frankly he plays at too heavy a weight. And also gets tired at that usage/weight and suffers defensively.
4) He's extremely valuable due to that floor-raising offensive usage.
5) I don't think that heliocentric style of offense is effective at winning championships compared to a more balanced approach. You could give White and Horford and Holiday to the Mavs and their ball movement would not be as good and he would still be a weak link who would be targeted on D. That matters in the playoffs.
6) The Mavs play that way because their talent isn't as good.
7) But when they had better talent like Jalen Brunson, they didn't recognize it or reach his full potential due to Luka having the ball so much. Brunson averaged 16 points in the playoffs for the Mavs with Doncic and 30 in his career in the playoffs without him (32 per in 3 games with the Mavs without Luka).