It's an interesting mirror to the system in Europe (including UK) and the US. In our countries, we deal with radical corruption (in all parties) by ignoring it, because each party decides it's better not to upset the apple cart. They're corrupt, but if we go after them, then our turn comes. So almost everyone gets a pass, as long as they are part of the "pig" class. (h/t Orwell).

The Peruvians are the other side of the mirror. The two sides of the elites (essentially communists vs corporatists) consistently go after each other. You are correct. ALL Peruvian presidents end up in prison. It's a radically unstable system, with nobody ever having the chance to "accomplish" anything, because the corruption involved in all Peruvian deal making brings them down in months.

So which is better? Permanent instability where nothing happens because there is constant chaos, or permanent corruption where the pigs keep getting fatter off the fruits of what they "accomplish" while the regular Joe keeps falling further behind?

Neither society is growing; both are in decline. Pick your poison...