Yes. The problem is that the government tends to take money out of that 'special pot' for general budget shortfalls. It doesn't help that projections for future pension payouts tend to be overly optimistic as well.

This and the fact that when state pensions were getting good returns - they setup guarantees which became liabilities of the state. However, when investments went the other way - the guarantees were still in place. So they get to have their cake and eat it too.