What are the limits of relying on export-led growth for Latin American countries?

In the twentieth-century, there were two main schools of thought on how developing countries could successfully grow their economies. The first, import substitution, was dominant in the 1950s and moving into the 1960s. In the latter part of the 1960s and into the 1970s, however, it was increasingly replaced by export-led growth. A number of South and Central American countries have experimented with both types of policies; although, some were slow to adopt export-led policies compared to their counterparts in East and Southeast Asia.
While import substitution seeks to build up many of a country's domestic industries at once by insulating them from outside competition (usually through tariffs) and creating a domestic market, export-led policies generally focus on a smaller number of industries or products. Export-led growth requires that a country specialize in the production of certain raw materials or finished goods and become the world leader in that production, thus increasing the country's exports and bringing in trade revenue from outside the country. Some Latin American countries chose agricultural goods, like bananas or coffee, as their trade leaders for export-led growth policies. Others, like Mexico, tried to strengthen their manufacturing capabilities and induced other countries to lower their barriers to trade for those manufactured goods (e.g., as Mexico has done through NAFTA).
There are certain factors that have limited South and Central American countries' success in export-led growth strategies. First, they were late to enter into export-led growth policies in many cases, which may have negatively impacted their ability to become early movers in high-tech products (like Japan and South Korea were able to do). Second, to the extent their policies relied on export of agricultural products or other raw goods, such as oil, they were subject to the whims of global demand and to stiff competition from other countries producing the same raw materials. A dip in commodity prices for a country that relies heavily on one or two raw exports can have a disastrous ripple effect throughout the rest of the country's economy. To the extent their policies relied on open trade (for instance, Mexico's reliance on favorable trade terms with the US), their success was dependent on other countries' willingness to accept their imports without imposing high tariffs. Finally, negotiation of favorable tariff terms for their exports generally forced these countries to accept favorable tariff terms for imports from other countries in return. This destroyed the domestic market for certain goods that could now be obtained more cheaply by importing. While free trade is supposed to be economically efficient in the long run, in the short term these disruptions to domestic markets were costly because they created job loss and other serious shifts in the market.
There are also general structural constraints that limit how effective an export-led growth policy can be. Most importantly, many export-led strategies rely on cheap labor, so that the exported good can be produced at one of the cheapest rates in the world and the country can retain its competitive advantage. As an export-led growth strategy is successful, hopefully the overall economy in the country improves. With a growing economy will come a higher standard of living and demands for higher wages. A country may eventually "grow out of" its ability to produce the low-cost good as wages increase. If it does not have a higher-quality or higher-tech export ready, for which importing countries are willing to pay more to support the higher cost of production, then the export-led strategy will no longer work.