Argentina still has Lautaro Martinez, Julian Alvarez, and several other names. Messi, certainly not serious injury. Likewise with Di Maria, some news claims Di Maria only needs a month to rest for his recovery.
On the other hand, IMO, losing N'golo Kante, Lucas Fernandez and Pogba, will not have much effect on Didier Descamps' squad. they have several names for a suitable replacement candidate. Didier Descamps only needs a mature strategy and chemistry between the players.
But, fans surely going to miss few players those are involved in good combinations which are going to be useful for the top teams specially like Dybala and Paul Pogba as most chances he is going to miss world cup because things are not favoring him for joining team and giving his best which is also good for the player and his career because this is also important for him to take time instead of doing things in hurry.