This has a lot to do with it. Messi is a fantastic footballer, amazing technical ability, but has struggled on the world stage. Plays brilliant in friendly games and against lower class opposition like Ecuador, even Panama are higher rated than Ecuador, but has always struggled when the pressure is really on.
Messi doesn't inspire players around him to get better, that's why he needs good players around him. And it's the difference between him and Ronaldo. Not saying Ronaldo is better than Messi, but, he does have a really strong personality. He is larger than life and players respond to this and play better than they normally would.
Compare Ronaldo on pitch in the last two games to Messi. Ronaldo has his head up, is sprinting from defence to attack, working hard on both ends. Messi is just standing around, rarely moving, not looking like he wants to play at all.
Look, I know the manager might be crap and things might not be going well, but, this the World Cup. The hopes of nation were/are on Messi's shoulders. I believe truly great players find a way to influence the game on the biggest stage of all. There is no excuse for not putting in effort. Show some passion for the Jersey that you are wearing.
I don't think he is finished, He will go back to club football and play his usual game for a few more seasons, don't think he will play for Argentina again though, maybe he should have stayed retired.