You are fundamentally arguing that cryptocurrencies, all of them, will be gone? That like 30 years from now, there will be 0 things that are basically cryptocurrencies or something that replaced them?
By analogy: two decades ago, US consumers were buying almost a billion dollars' worth of photographic film a year [1]. Photography hasn't gone anywhere -- people are taking orders of magnitude more photos than they used to -- but if you had invested your entire net worth into Kodak in 2000, you'd be penniless now.
Is this a serious argument?
Consider, what happens if the Internet dies? Well you could run a private coin on an old laptop, but that's not really meaningful.