So if inflation is running at 15% per annum, your cash value is depreciating at 14% per year (assuming you are earning 1%) which is absolutely devastating. With stocks, you are keeping up at 85% of inflation which is a lot better than cash.
But it takes a lot of courage to stay the course on equities with their ultra-high prices and valuations right now. If there's a big market correction (which many are predicting) it could take a long time to make that up in a high inflation environment.
Want to become rich, and believe inflation is coming?
You can still buy inflation insurance hedges for a fraction of a penny on the dollar.