Well of course there's no way to prove it now. Could you have proved how revolutionary the internet would be in its early days? You have to be open minded and extrapolate from the principles of the new system and its interactions with society at large to _guess_ how impactful it may be. I believe the fundamental principles of crypto (open, permissionless, decentralized, global, neutral, etc.) make it highly likely to revolutionize finance.
I agree that gold and Bitcoin have some very key similarities, but gold and crypto in general are quite different. With regards to Bitcoin, yes they're both stores of value, but Bitcoin has the added ability to transact globally and be much more divisible. Bitcoin seems to have settled into two roles within the greater crypto ecosystem; store of value and reserve currency for the entire crypto economy. Now there are also things happening in the Bitcoin payments space using lightening, but I don't think there will ever be a large appetite for payments using a deflationary currency (It's your savings account, not your checking account).
But outside of Bitcoin there is a ton of cool stuff happening in the DeFi space which could have big implications for our financial systems. One example is stablecoins which has a much better chance of being used in payment systems than a store of value like Bitcoin. In general I don't see this stuff replacing the financial system so much as finance companies slowly adopting crypto on the backend. Just like companies adopted internet technology as it allowed them to run more efficiently.
I don't think crypto will replace the financial systems we have or that we should burn down what's already there. I think the way it will play out is that it will increasingly get used on the backend of the legacy financial system. So the front end will appear similar to the consumer with the same usability and protections they're used to, while the backend will be settling transaction using a variety of crypto networks. The consumer will then have the option of using the centralized front ends or communicating directly with the decentralized crypto protocols.
I think part of the problem is that DAO (decentralized autonomous organization) is simply a poor way to describe what these new orgs are. Yes they're decentralized, but they are not fully autonomous, as they still require people writing code, making proposals, voting, etc. I think a much better term is "decentralized open organization" DOO. This captures better the fact that this revolution is about a new type of human coordination, not automation, even if a lot is automated. I think it helps to frame this as a social revolution to understand the full power of it.
Advances in the ability to coordinate humans often leads to great advances in society and technology. Now where crypto is immensely useful, is that in the past a decentralized group of people would have still had to be tied to a specific nation for banking. Now with crypto, a group of people from all over the world can run a company that's fully internet native that relies on no single nation for it's banking needs. You may not see it, but to me that is a ridiculously powerful concept.
But there's no reason consumer protections, user friendly addressing, and other features can't be built on layers above the base crypto protocols. For the monetary system to be optimally flexible the base layer should be fully neutral and permissionless. Then there's nothing stopping people from building crypto banks on top of those base protocols, which could add in consumer protections like refunds. Think about the internet, it's powerful because the base layers are neutral, allowing for the free flow of information.
You make a good point about software development in general, but I don't think it applies to things as fundamentally revolutionary as crypto. Sometimes system _do_ have to be completely re-thought from the ground up. I don't believe it's possible for our current financial systems to morph into an open network for storing and transmitting value (the internet of money as some call crypto).
sovereign store of value (useful if your government sucks)
permissionless payments (funding wikileaks)
private/anonymous transactions (Monero)
event tickets (good use of NFTs)
synthetic assets (anyone/anywhere can speculate on TSLA)
decentralized asset exchange - AMM
decentralized prediction markets
DAO - a new way for people to organize and form internet native companies