Don't forget this is real money, that the individual pilot has paid in over his / her working life, out of earned income. It is a savings scheme, and if it was left on deposit in a bank/building society and not returned in full, there would be an investigation and public uproar.
It is not like the public sector pension paid out of tax payers contributions (ponzi scheme), but earnt money put away and unable to draw on until reaching the plan/retirement age.