Because when these pals of yours started work, their lifespan was expected to be X years and inflation/interest rates gave predictable investment growth rates to cover the known mortality statistics.
All that went out of the window in the early noughties. The ONS admitted their collosal error in lifespans, so your pals are going to live for X+10, X+15, X+20 years at the very point when interest rates went from
6,7,8%+ to 4%-. Brown also forced the private pension providers to SELL a lot of their equities (at the worst possible time, after the DOTCOM crash) and buy all those gilts that he was furiously issuing to fund a quadrupling of the NHS budget, and other stuff.If your pals kept to their side of the 'contract' and died at the age they were expected to, then we wouldn't have so much of a problem.