As usual, you have attempted to weave a whole cloth out of a piece of straw. Nowhere in his white paper did Nakamoto suggest that his technology would "replace" traditional currencies/banking.
Perhaps not outright, but it was strongly implied. From the introduction in the white paper:-
Commerce on the Internet has come to rely almost exclusively on financial institutions serving as trusted third parties to process electronic payments. While the system works well enough for most transactions, it still suffers from the inherent weaknesses of the trust based model... What is needed is an electronic payment system based on cryptographic proof instead of trust
While it only talked about commerce 'on the internet', everyone could see that this is where commerce was heading. Furthermore that Easter egg in the first block shows the inventor's true goal, to replace the 'trusted' fiat banking system with something 'better'. Early adopters and proponents of Bitcoin were being honest when they promoted it as 'the future of money'.
Let's not forget that PayPal was bought by eBay six years before Bitcoin was invented. The proximate use case for Bitcoin was already being provided by a popular fiat solution. So why push Bitcoin? It actually languished for years as a curiosity that only wild-eyed libertarians imagined would take over the world. Then an actual use case was found for it - crime.
But it wasn't until the MSM reported on its potential for speculation that Bitcoin really took off. Bitcoiners switched to calling it 'digital gold' reinforced with an image of a gold coin impressed with the Bitcoin logo. Such imagery has a powerful psychological effect, used both by promoters and skeptics in the media. The result, as they say, is history.
Whatever Bitcoin's original intended use was is now out the window. Currently it takes about an hour to process a Bitcoin transfer, and that's with it only handling a small fraction of the world's monetary transactions. The stated goal of reducing the minimum practical size for small casual transactions is forever beyond its grasp. But nobody cares because that's not what it was ever really about.
Why do libertarians decry fiat currencies? It's not because they fear a collapse of the banking system (which has been remarkably resilient since the world moved off the gold standard in 1971), it's that they hate the possibility of their stash eroding in value. In short - greed - the same reason they hate taxes and the government doing anything to help others. That's the real reason they like Bitcoin, and why its total failure as a low cost transaction method doesn't bother them.