But all parties in all elections have been neoliberal parties. Not sure how you parse which one is the real neolib party and which isn't. Despite Slavoj Zizek's raging hard-on for it, Syriza was still a neoliberal party: it wanted to stay in the euro, which would require it to accept neoliberalization. Even though Syriza would have pushed for something a little kinder, austerity would still have been the dominant way of dealing with the crisis.
The Mexico situation is even more complicated than that. PRI has traditionally been more "socialist" (nationalizing, etc.) than a lot of ruling parties, and even if it's horribly authoritarian and paternalistic, its politics are less neoliberal than PAN's. On the other hand, the PRD talks a good game but spends a lot of energy fighting off leftist elements in its ranks and has shown itself to be more than amenable to austerity.
None of this is to necessarily argue with your thesis, but using election results to come to it is horribly wrong.