Because Xavi is not Argentinian.
well actually...
individualistic players (Di Maria, Aguero, Higuain, Tevez, Banega) are playing for themselves and team players (Zanetti, Zabaleta, all the defenders) are not of a sufficient quality. although Zanetti could make a solid pivot, I think, he doesn't have the legs for FB. maybe WB. I dunno. basically when only Badger, Gago and Messi are committed to the team game, you have a problem.
the key is coaching.
you need to harness talents like Di Maria and get him playing for the team. you don't have to crush his individuality, but you need to make that maverick streak work for the team. you need a system which allows top talents to play together, but also flourish together.
To Be Continued in the Argentina thread...