In my humble opinion, talking only about the 2026 World Cup, the two players could participate, but not playing all the time and perhaps not even as starters
They could be the player with the most experience, to give morale to the team, to help the new players, to come on in the second half or play a few minutes, take free-kicks, penalties etc
And I've seen several teams that have used this tactic
That's my bet for both of them to go to the '26 World Cup
These players have even become legends before they retire. I don't think they would like the idea of waiting on the bench and hoping their team to win the matches. However it isn't even certain if both of these players will be in the World Cup.
I doubt Ronaldo more because of his age now. He is still enjoying his game in Saudi Arabia now but maybe in the near future he would announce his retirement who knows.
I also think the same as you, personally I have always seen that things with these players are always very controversial, with the case of CR7, he is a player who will always be the best in everything, but in Qatar the friend and coach He did not want to put him in the game, something that caused a lot of indignation in Portugal, until now the Portuguese has not forgiven the coach for that, now he is currently in the team and is doing a very good job, although there are one or another player who criticizes him a lot And that can bring internal problems, especially Cancelo because he is a player who has basically given some statements that were not well received, apart from Messi and Argentina, things have gone much better, because Messi is a fundamental piece for the team, so Given these things, we are people who will always take for granted that he will have no problems being in the World Cup. The thing about CR7 despite his great performance is still debatable, many think that because of his age he will not perform, but I have see this does not affect him, his training regime is very strong and sometimes he has more speed than a 20-year-old player.
I think the biggest reason why Portugal will probably have to play Cristiano Ronaldo is because they have not found a good replacement. If they actually had found a good replacement, there was no reason for them to play an old player like him in the main squad. And just because he is old does not mean he's obsolete. Even at this age, he is scoring a lot of goals without much trouble. I mean he might not start a few matches. But he is not going to be a regular bench warmer.
I am actually not sure about Lionel Messi. Will he be even interested to give his 100% in the next World Cup?
I don't know. But I believe if Messi actually wants to play the World Cup, he is going to give his 100%. And he is definitely not going to be on the bench too much of the time. After all, he was the hero for Argentina in the last World Cup.
But I guess we all know that these two do not have as much of an impact on the whole world as they had previously. So it is probably going to be Argentina versus Portugal even if it happens, it is not just going to be Messi versus Ronaldo.
They can't find a replacement because they won't want to find a replacement and they still think about respecting Ronaldo because he is a great player for his team while that's wrong and they should start seeking.
In fact, they can't find any player because they already have Ronaldo on the team, I think the best thing he can do is to get retire and that's how he can force Portugal to find an alternative player because then they will understand they can't use Ronaldo anymore and they have to find another player instead of him.
replacing ronaldo is not an easy task, since many years ago portugal never had a player like ronaldo, they had good players like eusebio, deco, luiz figo, but all these good Portuguese players did not even reach 50% of the level of Ronaldo has been doing this since 30 years ago, so it wouldn't be now that they would find a player like Ronaldo, to get an idea of what I'm talking about, in this article they talk about the 10 best Portuguese players of all time, look at the list of the 10 best Portuguese players of all time. Everytime:
https://www.givemesport.com/best-portugal-players-in-football-history/
Ronaldo scored 128 in Portugal, this is counting the games he played for the Portuguese national team, so look how many goals the remaining players on this list scored, you will see 9 players on this list didn't even reach 50 goals, just Ronaldo alone managed to score goals that even if you add the number of goals scored by 7 players on this list, it still doesn't surpass the number of goals scored by ronaldo. So Portugal won't have another Ronaldo, maybe in 10 or 50 years another Ronaldo or another Messi will emerge. This generation of players is very weak. In the past we had Ronaldinho, a true football genius, we also had Brazilian player Ronaldo, we had Zidane, they were players who, when the team was doing poorly, could solve the game.
but nowadays you can no longer find players at the same level as ronaldo and messi and the good players of the past, this is a reality, when messi and ronaldo retire, then we will wait for one day, many years from now, good players at their level will emerge , this would take many years. I don't believe that in Argentina there will be another player at Messi's level so soon. It's even strange that 20 years ago the level of good players was high to the point that current players can't surpass those players from 20 years ago. Football nowadays is very linked to marketing and money, so it's unlikely we'll see another messi or another ronaldo