Argentina was a good enough team in the last Bishcup. But their main weakness was their weak defense. And this is why Argentina's performance in previous World Cups was not very good. But in this World Cup, Argentina is a self-sufficient team. Defense, midfield and forward players are in good form. So in this World Cup Argentina team is considered as favorite by all. It could also be Messi's last World Cup. So most Messi fans want Argentina to win the title.
It's his last chance, and Argentina arrived to this world cup unbeaten, so it's a really good chance for him. It's literally now or never.
I have yet to see any official news where Messi has announced that this is his last World Cup. However, Messi is now 35 years old, so naturally, this is going to be his last World Cup. And Argentina is expected to do well in this World Cup. Because the Argentina team has been able to continue good performance for a long time. I would say if Messi and Argentina's defenders are able to perform well in the World Cup, Argentina has a high chance of winning the title.