This makes it clear that we must be careful to distinguish between the ledger (a conceptual spreadsheet keeping track of who owns what percentage of the economic community known as "the Bitcoin ecosystem" and later perhaps just "the global economy") and the protocol for updating that ledger.
We're back to this silly idea of separating the currency from from the blockchain. You can't, they are one in the same.
This "ledger" rhetoric is a paraphrase of the false idea they are separable.
The system is the blockchain is the currency is the protocol is the ledger.
You're not reading.
The Bitcoin protocol specifies the parameters of the ledger (including coin issuance schedule) and how it is updated, but that doesn't mean you can't have a different protocol that
maintains the same ledger and issuance schedule but that accomplishes this task differently under the hood. This has nothing to do with the "separate the currency from the blockchain" meme that is floating around.
Mining fees do introduce some ambiguity if they are set extremely high by the protocol and somehow cannot be user adjusted, because the effect would be similar to changing the coin issuance schedule. But that seems a moot point because users would find a way around the default setting if fees were so high as to make a difference.
Yes I already acknowledged that some aspects can be changed but neither can arbitrary changes be made, as you point out.
Other changes one might imagine are include the sorts of variable demand-sensitive block rewards as described in Vitalik's post. With fixed block rewards Bitcoin is inherently subject to enormous price volatility in the presence of any demand volatility, and that
may over time turn out to be non-viable.
It is foolish and short sighted not to realize that bitcoin is an experiment in progress, and
may have gotten one or more fundamental things seriously wrong.
Before you assume I'm trashing bitcoin here and respond accordingly, note the emphasized use of "may" in both of the above paragraphs. Serious risk factors exist.
Also note that bitcoin is priced for at most a 0.1% chance to succeed in a big way on the scale of fiat. If you think the probability is actually 1% then you should bet big on bitcoin, but it can simultaneously be rational to bet on alternatives that might succeed on that scale instead of bitcoin.