Some of the fund managers there make more than the managing director, but still, we're talking about a "modest" figure in the $1mm-$2mm range. That's paltry pay compared to the big bucks made in hedge funds and private equity.
The pension fund could have paid out hundreds of millions to their fund managers, and it would only have been a rounding error in the grand scheme of things...but still they manage to attract top talent.
There's this culture on Wall Street (or Connecticut, or London...) that they are the only ones that can bring big returns, because they're the right combination of correct pedigree, professional experience, network, talent, etc.
In the end, it's just good salesmanship. Tons of funds deliver mediocre returns, while making bank.