Having spent almost 13 years of my life living in Argentina, including the bulk of Maradona's prime, allow me to call you an idiot.
If you take basically everything you wrote and made it say the exact opposite, you'd be correct. Argentines revered (and still do) Maradona for precisely the mestizo, rags-to-riches journey you say embarrassed them. They love Messi because he's a world class star, not his skin tone. WTF?
Messi "ran away" to Spain for the same reason Maradona ran away to Italy (and your beloved Tevez ran to Brazil, then England, and now Italy). It's called money. There is no money in AFA, at least not by comparison to other leagues. Hell, dudes make more money coming to the MLS than they do down there. Argentina has always been an exporter of world class soccer stars. One or two brilliant seasons with River, Boca, San Lorenzo, Racing, etc., and you're almost guaranteed a job in a big European league. The AFA is basically triple A for the big leagues. It pains me to admit that since I'm a die hard River Plate fan, but facts are facts.
Tevez is loved in Argentina, warts and all. He plays with a ton of passion and heart. Sadly, the national team is still plagued by politics, favoritism, and tends to stick with the old guard even when they're washed up. I don't know where Tevez is on that spectrum of favoritism, but he may be on the outside looking in.
Also, Messi has never given up on Argentina. Germany has been better than them consistently. It's been that way since 1990 in Italy when they lost to West Germany in the finals.
Although he's the best in the world, I will agree that Messi's legacy will suffer if he doesn't lead the Biceleste to victory in one of the next two WCs.