Because talented engineers don't want to work on the typical things that get outsourced, such as maintenance of legacy applications, helpdesks, implementation of dull ERP projects and so on. Therefore on average the quality of programmer at an outsourcing company is lower than at a real product company, and this would be the same at any outsourcing company in any country. It just so happens that some locations are cheap enough to make hiring large numbers of low quality engineers seem more attractive than fewer, high quality engineers payed sufficient salaries to attract them.