You have to understand that bitcoin's innovation was 30yrs in the making. Solving distributed global consensus was a breakthrough in computer science. There has not been a single innovation in the alt space that even sorta compares to that. Not one. Which is why bitcoin is highly likely to remain dominant.
Furthermore, it's been well understood for the past 20-30yrs that if you could solve distributed global consensus, you could do digital cash, and it would be a big deal. It's just that no one had figured out how to solve double-spending (global consensus) prior to Satoshi. There is no similar known problem being attacked in the alt-space for which a solution would be a breakthrough of similar magnitude. So an alt would have to luckbox into some completely unforeseen yet incredible innovation.
I sort of agree.
However, the question I would ask is whether distributed global consensus has actually been "solved." Bitcoin has significant issues with centralization (i.e. not necessarily distributed in practice) and also significant longer term issues with how to support distributed mining (if that even still exists at all) once block rewards go away (or drop to insignificance). Finally, true digital "cash" is probably less traceable than bitcoin.
Further, it is not clear that even today mining (costing several hundred million dollars, i.e. a large percentage of total capitalization) provides a robust and persistently useful trade off between cost and security.
It seems possible that in 20 years there will be a better solution that was 50 years in the making, with bitcoin as one piece that fell into place just as others fell into place over the last 30.