well to be honest you might be really wrong about that, bitcoins can actually last for a long time though i really doubt that it is not going to die in the future because of a huge variety of reasons

first of all there will be some other currencies that will be even better that bitcoins, i mean not only other type of cash but also the other cryptocurrencies that might be even better with their code and so on

besides that i think that bitcoins might not even become as big as fiat is right now so there would surely be some trouble for it staying around if the rate of adoption does not get way faster than it is right now

so i wouldnt put too much hope into it right now because in my opinion in the future anything might happen and you would just lose big money if you invested too much into it