Argentinian here. The problem is a bit more complex than "populism", because of course if non-populist governments were handling the country perfectly, there would be no risk of "populist" options.

The causes for the problems in Latin America are complex, there is no single root cause that can be easily explained in an Internet forum, and keep in mind many of these countries -- well, I can at least speak for Argentina -- were historically owned and managed by decidedly non populist landowners which influenced the following generations of leaders (and some of these families still own portions of the country). So if populism was a reaction to conservatism and prior authoritarian governments, it cannot (alone) be the root cause of our problems.

Sure, corruption is a problem as well, but I think that alone it doesn't explain our problems either.

I think corruption and populism are more symptoms than causes.