Unsure how large of city you were near... more rural/tourist areas you will see less or maybe experience no issues. I would move to Patagonia area in a heartbeat here in Argentina... there is very little of the crime so to speak, but fewer people as well (I live in city of 1.5 million people).
If you go to larger cities here in South America, there are shanty towns that would remind you of the great depression in US history. These are not small areas either and are growing... the very poor literally live on dirt floor with brick walls they build.... a greater majority of population lives in poverty in 3rd world compared to USA/Canada/Western Europe. The thieves typically now ride small motorcycles that are very common.. so they get throughout whole city very easily. No areas are really immune unless you lived in what they call "closed neighborhoods" that are becoming more prevalent (gated community).
Several reasons... global economy is one... but also increase in drugs here and corruption of the governments.
I actually could do without all the stray dogs