I admit that I am having a hard time with this. I thought after Game 5, that Tatum would win the MVP award. I was surprised that Brown won it. For the series, Tatum had more points, rebounds and assists, while playing against double and triple teams all series. Brown had a better FG% (worse 3P% and FT%), more steals, fewer TOV, more blocks, and a better overall +/- (many of these were pretty close). I would say that overall, Brown had more impact on defense.
It is close, no matter how you slice it, but I don't know how you can look at the stats or just watch the games, and conclude that Brown was more valuable than Tatum. Tatum is the better player, DAL knew this, that is why they focused on stopping him so much, and Tatum was the better player in the finals. I would love to hear some of the voters explain their thinking.
The only thing that I can say is that relative to expectation, Brown probably exceeded expectation while Tatum probably came up short of expectation. But MVP shouldn't be a handicapped selection. The expectation for Tatum based on the season and his career, was higher than the expectation for Brown. It is like comparing a 5 handicap golfer who shoots 3 over par with a scratch handicap golfer who shoots a 2 over par and saying the 5 handicap golfer did better.