Bitcoin being the first cryptocurrency, I think it will always be a future of cryptocurrencies. As old altcoins will be replaced by new altcoins and the chain will continue by replacing old with new and forgetting the old ones. Bitcoin is rapidly increasing and so it'll always have its own class and importance. As simple as bitcoin do not have anything to get replaced with so it can be considered as a great future.
Many people have the impression that since bitcoin was created 10 years ago now it should be old technology that should be easily surpassed but that is not happening because most coins in the market are direct copies of bitcoin, and it is completely impossible for a copy to replace the original, in order for bitcoin to be replaced a new coin with superior technology will need to appear and so far that has not really happened and I am beginning to have doubts that will happen during our lives.