> fixed total amount of Bitcoin that will ever exist
It has a fixed supply. (Currently. An unknown number of miners could always increase it.)
> Bitcoin is not inflationary
Of course it is. One Bitcoin buys 75% fewer goods and services than it did a year ago. Taking advantage of people who mistake money supply for inflation is one of crypto’s scams.
When one says bitcoin is not inflationary, they mean that the supply does not inflate. You are accurate that bitcoin's purchasing power can wane aka deflate. In my opinion and many others it is moot because everything deflates. As far as we know, there is not a single thing in existence that is void of inflation by your usage of the term. Therefore, we move beyond that version of the definition to the practical and useful definition which is that it cannot be added to numerically.
English is my first language and those sentences are crap, but I think you get what I mean.
> When one says bitcoin is not inflationary, they mean that the supply does not inflate
This is wrong. Not matter of opinion wrong, factually wrong.
> bitcoin's purchasing power can wane aka deflate
This is also wrong. Waning purchasing power is the definition of inflation. Bitcoin was marketed as an inflation hedge. It hyperinflated. Solving that by redefining inflation is dishonest.
> the practical and useful definition which is that it cannot be added to numerically
This is the opposite. It’s taking the practical definition, which relates to purchasing power, and replacing it with a technical curiosity. Which is also, again, wrong: a small group of miners can amend the protocol to keep the gravy train running.
You mean a large group of miners, right? And please don't negate what someone says with just "that's wrong". How is that helpful? I clearly said the literal definition of inflation is not useful because every single thing in existence is inflationary meaning bitcoin is as inflationary as every other thing. We use the term in regards to money as meaning the supply doesn't increase and I believe you are fully aware of that.
Bitcoin hyperinflated in the last year.