Artificial intelligence and Big Data are the next big things. It will take 20-30 years maybe, but we will turn to use it for sure in the future for anything in our life. It's already used but by the time we will have a better technology.
Blockchain probably won't fail, along with the advanced tech upgradation it will grow and develop more rapidly. AI and Big Data as you said will also be the next big thing. IT industry is in the search of AI, Blockchain and Data professionals and it is growing, showing good signs of the upcoming revolution. Probably Blockchain is a system, and upon which cryptocurrencies function, so coin might fail but the technology will be there.