It does not occur to me in any way that cryptocurrency is the only coin that can be the future of the entire cryptocurrency. However, I believe that one of the best cryptocurrency coins is Bitcoin. However, in addition to Bitcoin, there are other potential coins on which the market relies a lot. So Bitcoin alone can in no way be the future of cryptocurrency.
The future of cryptocurrency cannot have the scalability of seven transactions per second and the high transaction fees that bitcoin currently has. Many altcoins already have the ability to provide a million transactions per second, and they are carried out for free or almost free of charge.
The current popularity of bitcoin is mainly based on the belief of its holders that bitcoin will continue to grow in value for the foreseeable future. As soon as its price growth stops, it will rather quickly lose its leadership position.
The future of cryptocurrency belongs to those coins and tokens that will have high utility and have the most acceptable functional qualities. There are many contenders for this now, but they will still change, since the cryptocurrency is developing rapidly.