"Yet Prebisch also worried that economic efficiency would be sacrificed if developing countries, with their very small domestic markets, tried to pursue a policy of self-sufficiency." 
Nurkse’s early questioning of import substitution later turned to outright criticism. By the end of the 1950s, he argued that import substitution would draw resources away from the export sector and “may lead to costly and inefficient production in import substitutes,”
(Studies on #Pakistan) John Power (1963, 201) concluded that the lack of competition because of import restrictions meant that there was “just a lot of plain inefficiency” in Pakistani industry.
“in short, doing many things poorly instead of fewer things well.” ... " Ronald Soligo and Joseph Stern (1965) calculated that many Pakistani industries had negative value added at world prices."
