If bitcoins died tomorrow i would convert all my bitcoins to litecoins and keep it as it is until and unless the price of bitcoins rise to a very high amount and transact it day by day so that i can have a happy life.and enjoy it to the. Fullest . 
If bitcoins die tommorow, i will convert it to fiat and move on. Look for another cryptocurrency that can replace bitcoins. I know its hard to look for another cryptocurrency that as high with the value of bitcoins but i must move on. This speculation might happen, theres no impossible things in this world so we better get ready so once this happen, at least we already know what to do.