Argentina looks strong on paper but its mostly in attack. Goalkeeper and defence is weak, midfield lacks a playmaker and the attack consists out of personal glory chasers.
Messi carries that team, not on a Maradona 86 level (allthough he did in the last copa) they have been unlucky. If they were better at penalties and Higuain not the biggest choker in the game they would have won a wc and two copas in recent years. Reaching those finals is amazing considering the lack of chemistry, bad coaching, poor management and Messi needing to do everything alone in attack.
If you want one example of the huge difference in The mindset of Argentina players compared to Barca look up that one di maria goal. Where Messi dribbles 2 players , nutmegs anothers one where they crash into each other. Pastore ends up in a like 3-1 situation where at Barca Messi always gets that ball back. Yet this selfish idiot shoots for Di aria to score the rebound.
Only thing Messi could have done is go full dictator. Demand coaches, replacements at the federation, everyone playing to serve him and pas the ball when possible. Not think they are better and screw up his dribbles by shooting it out of the stadium. Unfortunately the guy is too nice and quiet, thus get scapegoated every time they dont win a trophy.