https://www.weforum.org/agenda/2017/10/sweden-could-stop-using-cash-by-2023?utm_content=buffer40bef&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer
For me the word extinct is not very much appropriate, the cash will just be reworked or they will be upgraded. Because for me every country will not let the bitcoins as their official currency because of the fact that it is no stable the value do not varies day by day so it will be hard especially for ordinary people. And the second one are because of the fact that they are decentralized and the Government surely do not like that so the more likely to happen is for our cash today being converted into a digital version