That's the problem you all have though. Although inflation isn't the natural state of fiat currency even if it has been corrupted to this your purpose should not be to accumulate wealth purely by having wealth. You're not supposed to keep 100 dollars under your bed for 50 years hoping it grows to 5000 or even remains the same.
What you used to produce when you were payed 50 dollars is now produced for 5 dollars in a more efficient economy.
So what happens when you get to old to earn a living?
You have state pension/private pension investments into the actual economy.
Or you have a social security system in setup in which a new generation takes care of the old.
It can even be into state papers that barely pay an interest above inflation but are thus extremely safe.