I'd say it will be dead. But that's not a bad thing. Bitcoin and other relevant cryptocurrencies are just an evolutionary step and there is no need to think it's here to stay forever. Bitcoin paved the way for something revolutionary and other future cryptocurrencies will build off of that idea.
The other option is that Bitcoin becomes to crypto what gold is to FIAT, a more or less stable standard.
Yes I agree with you. Changes in the world can not be predicted with 100% correct. The success of something has its limits and there is a period of dim. For the next 100 years bitcoin could be lost in the circulation of the internet. And there will be others that are more advanced than bitcoin. I can't be sure of that either. Let the world see it.