It would be strange if they didn't leave the national team after this championship - after all, it's the pinnacle of a four-year cycle and their age means they won't make it to the next World Cup. It's better to leave on time than when you're dragging the team down. By the way, if I remember correctly, Messi has already ended his career in the national team several times and then resumed it.
Both Messi and Ronaldo countries don't have the best team on paper in this world cup. This is likely their last worldcup but these legends might still want to have few games with their national side after the world cup. In terms of an identity, cohesion and commitment, the Argentina team seems to be slightly better than that of Portugal and hopefully it will be a great worldcup for Messi.
I supported the Argentine national team when Batistuta played there and then for some time due to inertia, but now I will wish that this team did not go far in the upcoming tournament. I'm a little tired of the hysteria that is inflated around Messi and the last event (Argentina - Italy) reminded me very well of this. Argentina won and again from every iron I heard about Messi's genius. Please, I've had enough