I always saw the lack of priority at immigration as a demonstration of egalitarianism/irreverence which is a very Argentinian feature (and one that I am actually quite proud of).

There is a VIP package, though, where you are escorted to a separate lounge area, and clear immigration and customs there. Last time I checked, unless you had some premium Argentinian credit cards the price was 250 USD and I honestly don't think it's worth it.