The $300 billion California Public Employees’ Retirement System began showing its age this year: It started paying out more money to retirees than it gained in contributions and investments. In roughly 20 years, CalPERS’ retirees will outnumber active workers by a ratio of nearly 2-to-1 in some of its plans.

In fact, a lot of state and local pension systems are already showing their age. Back in the 1970s, the typical pension fund had four to five times more active employees than it had retirees. Today, that ratio has slipped to 1.5-to-1 and is falling.

In the investment world, fi