I think it will still be for a long time, as it is first ancestor of crypto currency. Unless it is banned by governments from all over the world, i cannot see it falls from grace any time soon.
I believe it will last long if we want it to. As long as there are
individuals and investors whom undoubtedly will utilize, support,
advertise, advocate and circulate bitcoins there's nothing to
really worry about. As technology further develops and there
is a lasting demand for btc and cryptocurrencies, bitcoin will
be here for a long considerable amount of time.