Why Outsourcing, not Open Sourcing?

James McGovern has a question (and another brilliant pic - where *does* he find them?):

Why do people outsource when they can open source? For example, if there are 250 P&C insurance companies in the US in which each may have their own claims administration system, why do they outsource individually to India instead of open sourcing the systems that are expensive but otherwise don't provide competitive advantage? Is it the lack of vision within the enterprise architecture crowd?