Ronaldo, Zlatan, Buffon or Cannavaro didnt win it either, arent they greats of the game?
WTF ? Terrible comparison
, it was a mere example but i'll bite, lets start, Ronaldo ,Buffon and Cannavaro all won the world cup to start with, so theres that, they were also at one point in their career the best in there position, next is they all played and won titles for massive european giants which granted it's not really fair to compare that as a negative towards Aguero but it's a point regardless, I won't even start with comparing Aguero to Zlatan, instead go to Zlatan's Wiki and view his honours,
Aguero is a fantastic player, but he needed to move to a bigger club and win titles there to be known as a great, it's as simple as that.
In 10 Years time most will not remember him outside the PL but the list you mentioned will all still be spoken about across europe.