This is a question probably best addressed by the pension funds, but I'll take a shot at it.
I think there are a couple of things at play. With respect to pension funds, the bottom line is that they tend to be risk averse, because they have to ensure they have a continuing stream of returns on their investment to meet their pension obligations. So they tend not to invest in greenfield projects because of that high risk, but rather buy assets around the world or invest in brownfield projects.