Like all digital technology, it is unquestionable that sooner or later bitcoin will have to be replaced by a superior technology, just as in the past we saw many devices become obsolete when at the time seemed insurmountable, such as CDs or PCs.
Obviously this will happen in a gradual way, but I do not believe that bitcoin can retain its current dominance for more than ten years before starting to fall into disuse, although perhaps its influence could persist in the market about ten years.
In the end, bitcoin is likely to subsist for many years, but by then it will have evolved in such a way that it will be virtually unrecognizable for todays standards, and in fact it is difficult that in 15 years there is something similar to the current cryptocurrencies before the spectacular advances in digital technology that are approaching.
Maybe it will not last forever but I think its too far away from now. Well if its bitcoin time to leave then we cant do anything about it. I know that people are making an investment better than bitcoin and it will beat bitcoin. But now , its better to focus in bitcoin rather than anything else. It may gone but the experience and the lesson it teaches us will remain.