Once upon a time, everyone worked for the MyTeaEst corporation, which produced one million loaves of bread in the year 2000. It paid its workers in bread, and they ate the one million loaves.
MyTeaEst also gave half of its workers a pension plan, promising them one million loaves of bread in 2025. It gave the other workers a 401(K) plan, where the workers deposited bonds issued by MyTeaEst that promised one million loaves of bread in 2025.
The year 2025 came. MyTeaEst still produced one million loaves of bread, with a new generation of workers. Those workers expected to be paid, in the aggregate one million loaves of bread. The older generation of workers on the pension plan expected one million loaves. And the older generation of workers with the 401(K) plan expected that their bonds would be repaid.