Policy volatility is about as significant a driver of Latin American per-capita economic growth as income inequality. Capital inflows and debt are insignificant; only U.S. interest rate volatility is comparable to domestic factors.
"Regarding macroeconomic policies, the higher the volatility of discretionary fiscal policy, the lower the growth.
...
Despite several episodes of reform reversals, most countries made progress in market-oriented structural reforms during 1970–2004, except Venezuela. The intensity of reversals was highest in Argentina, Bolivia, Paraguay, and Venezuela. Chile, Costa Rica, El Salvador, and Uruguay made the most progress during the 35 years. Greater market-oriented reforms and fewer reform reversals were associated with higher growth."
https://www.imf.org/en/Publications/WP/Issues/2016/12/31/Vol... pages 26 and 28; also see Table 17 on page 45
Maybe they had bad policies, maybe whey didn't, I'm not sure they'll be massively better off under any other system. If we're not talking about Cuba and Venezuela which have exactly opposite problem of failing to turn evidently unsuccessful decisions.