I am talking about people holding the currency 'pure'. Not those holding other assets like stocks in companies, land, houses. Even if their value is given in terms of the old currency, the return is denominated in share of profit, production value or rental value. But if you are hoarding cash, loans, bonds, with the return fixed in currency terms, that is a different thing.
The wealthy are usually diversified, obviously. Ad absurdum means just a look at the extreme crazy case. Reality may fall far short of that, but it is still instructive.
The world is seeing the introduction of a new currency. To understand what this can do, it is useful to look at the 'ad absurdum' argument of radically changing the currency asset.
Imagine a pretty island economy. Everyone goes about their business as usual. For as long as people remember they have been using black shells as their currency. Some people that have worked hard and done well have hoarded socks full of the black shells. They feel pretty secure they can live out their lives wanting for nothing.
Now shock horror! The people of our island wake up the next day and suddenly only white shells are accepted in the economy. People still working can expect to be paid in the new white shells and life will go on pretty normal for them. But those people that had hoarded the black shells can find themselves poor overnight. And other people that just happened to live on top of a pile of formerly useless white shells are the new wealthy elite.
Bitcoin has the potential to create a big change the worlds wealth distribution. Like a reshuffling of the cards. But don't expect those with a big stash of the old currency to take it lying down. Soon they will realize a switch is going on, and they will rush to get into the new wealth asset. This will be the great tipping point where the future distribution of wealth is decided.
False premise for today. The rich do not "hoard" any black shells, or fiat USD. Everything is invested somewhere. If you have stocks in Apple, and white shells become the dominant currency, Apple will switch over to the white shells as well to conduct and sustain their business. You were invested in the company Apple, not in black shells. Ideally you won't have lost anything.
The same in theory if you have black shells (resp fiat USD) in your bank account. Ideally, a bank is just an intermediary between lenders and loaners, and they would conduct the transition black shells to white shells pretty seamlessly. In practice and reality of course they're gonna use that scenario to rip off the clueless big time.