So when LeBron scored the last 25 of his team's points against the Pistons to get his team to the finals at the age of 23, you didn't see that as killer instinct or competitiveness? Come on now. Not every great player has to fit the Jordan mold completely in order to be a champion - see Shaq, Tim Duncan, Dr J etc. LeBron gave up at the end of game 6, but I don't think I've ever seen anything like that from him before. I'm kind of inclined to believe that something happened behind the scenes to make him decide that he wasn't coming back, and he just checked out mentally to a fatal extent. And that infected the rest of the team.
Wade hasn't exactly covered himself in glory since 2006, lest we forget. Sure, he's had less help than LeBron but he went down to the Celtics too, and first round exits have been the norm. His finest moment since then was the Olympics but in the playoffs, he's had very little success post-Shaq. See also - Kobe before Gasol. Winning a ring as a star perimeter player (i.e. the best player on the team) is just incredibly tough to do. How many have done it without a dominant big man? Jerry West needed Wilt, Magic needed Kareem, Bird needed McHale and Parrish, Kobe needed Shaq or Gasol. Isiah and MJ may be the only ones to have pulled it off in recent memory. Most championship teams have featured a dominant big man who was the top player on the team. There is a distinct lack of nuance in how America views its star athletes - everyone is either a hopeless loser or a glorious winner. The reality is they all just help their TEAMS to a greater-or-lesser extent, and some teams need less help from their stars than others.