Naturally, there must be a limit to the growth of money's value. As the value of money increases, eventually the individual benefits of holding more of it will go down.

This happens as the market cap of currency becomes a larger and larger fraction of the whole economy.

There are only so many errors that the economy produces for a cash-holder to take advantage of, and only so many tangible goods.

The economy becomes saturated with money once there are enough investors sitting around with piles of money such that they are able to catch all the errors that are financially worthwhile. (STAN: Is this because anything worthwhile is being caught already? i.e the supply is met by the demand the moment it comes, hence the value cannot grow)

At that point it is no longer individually beneficial to hold more money even if the value of money has gone up. This prevents the value of money from going up further until more people or businesses are added to the economy.

-- an excerpt from It's Not About The Technology, It's About The Money (2016), its 2-minute version can be found here: https://2minutebitcoin.org/blog/bitcoin-is-about-the-money-not-the-blockchain-technology