Bitcoin or any crypto not controlled by the deep sate will never become the worlds reserve currency however that does not mean they are not a severe threat to the US dollar. Most likely we will see a fedcoin issued by the US and other countries are looking into their own centralized electronic blockchain based private currencies or perhaps we will see beastmarkcoin as a world currency (hehe) whereby govts track ,monitor,tax and confiscate everyones money at will,but even with that there will exist the underground cryptocurrencies that can never be stopped and as more billions pour into crypto that is less in dollars that the banksters can profit from so crypto as a hedge against toilet paper money and as a currency in and of itself is a huge threat to the dollar. Why buy airline tickets with dollars when I can use bitcoin? Why do we need dollars very often when more and more hundreds of thousands of stores accept crypto and you can be paid in crypto? Can you see how the dollar is getting squeezed here? I welcome the day.