Economists have know for 500 years that a currency must have some inflation, otherwise people will hoard it and it will not be available for use as a currency.
During the past 500 years, there were long periods of effectively zero inflation where economies boomed. In the industrial revolution in Britain, for example.
Also, I don't think there was such a thing as an economist 500 years ago.
Gold and silver coins kept the price for a pint steady as a rock for hundreds of years.
Gold and silver has been the most trusted currency for a long time and it is inflationary. There will always be a supply of new gold and silver. Unlike fiat there is nobody that can manipulate the inflation of gold and silver.
A crypto could have a built in inflation that simulated gold and silver.
You know what that crypto is called? Bitcoin.
Besides, nobody knows the complete above and below amount of gold. There are some numbers, but you can't trust them if you ask me.
What if you found a 10000 kg pure gold meteorite in your back yard. You wouldn't tell anybody if you're smart.
That's one of the reasons why bitcoin is superior to gold. We know the exact current and future supply, no secrets.