You have to be kidding me, right?
Portugal has always been mediocre compared to Messi's Argentina's team and the different Real Madrid teams that Ronaldo has played for.
If Ronaldo played for Argentina, do you know how many world and continental titles he would have with them? SEVERAL. If you were to take Messi and put him on those Portugal teams, they wouldn't even get out of the group stages.
Now, I do agree with you about Argentina never embracing him, and that he spend/spends most of his life in Spain. He should have represented Spain like Diego Costa is doing, and maybe his path would have been different, but i doubt it. He does not have the game or body to really take over a game. He is an outstanding dribbler, and has great awareness. But he lacks physicality, pure blazing speed and athleticism, which are elements that Ronaldo has. You can't put a cross in the box to him, where he can win it in the air. He does not have the height. Also, he does not have the power on his strikes to be really successful as a penalty taker.
Case in point:
I'm a huge Chelsea supporter and have been following them since forever. We hate Barca like no other team, and we see them as our biggest rival( Chelsea really has no rival derby in the EPL like MU v MC, or liverpool vs everton, or Spuds vs Gunners), especially since there was a lot of cheating going on in the 2009 semifinal CL match. Anyway, Messi scored his first goal against us in this past CL. That was his first goal against Chelsea. You know why? Our physical play, and closing down the gaps, forcing Messi to play big, which is something that he can't do. Also, with the game on the line against us in the 2012 CL semifinal, Messi, again, missed a PK that would have given his team the victory.
Take him from the comfortable settings of Barcelona, and put him on a team or league where he has to play big, and he will not rise to the occasion. Ronaldo will. Ronaldo will find away. That is the difference
What will Messi be as he ages? Once his dribbling slows down, and he can no longer slip through the cracks, what will he be? Will he be able to reinvent himself like Ronaldo? We shall see.