About the future of Argentina after this year's game, I think they may not take many years to achieve another title because as most of the aged players will be retiring from football some of the younger players who have not been noticed will be given the opportunity to joining the national team and their performance will determine the time they will need to win another title.
Messi, Di Maria, and Otamendi may retire soon.
So, there will be a big change in Argentina squad without these 3 players. In my opinion, these players have a big role in Argentina squad, so Argentina will miss a big thing without them. Considering this, I doubt that they will win another title in the next few years. There are no players who can replace the role of Messi, Di Maria, and Otamendi.
There is no doubt about Kylian Mbappé ability and quality which he has done in this match but at the end Argentina won this match on penalties which is surely another chapter but performing while you are watched by more than a billion peoples around the world and having nearly 90,000 fans on ground is surely never been easy for any player French players done good job in regular time and in extra time but sadly on penalties they were unable to handle pressure and lost heir momentum which helps their opponents to win title after 36 years.
Of course, Mbappe showed a great performance. He even made Argentina almost fail to win the world cup trophy. Unfortunately, Mbappe was unlucky that 2 France players failed to score in the penalty shoot out. But he must be quite satisfied with his performance because he has tried his best until the end of the match.