I think that Bitcoin will have fallen in twenty years, as coins with more use cases appear. Bitcoin was the first and the most innovative, but as Bitcoin grew older, more revolutionary ideas have overtaken it. The market nowadays are dominated with privacy based coins and platform coins, which allow users to create applications on networks such as Ethereum and NEO. You can already see so many apps being vreated off of the Ethereum blockchain and i can assure you that we will see so many more projects to come.