One thing which will affect Blockchain technology  and maybe a lot of crypto currencies is Quantum computing which are now becoming more and more available.


"Quantum computers will destroy some of cryptographic principles behind blockchain. On the other hand, the very power of the quantum computer represents a threat to existing cybersecurity infrastructure. In particular, the quantum computer will destroy some of the cryptographic principles behind the blockchain"

Blockchain technology will have to change along with a lot of of other cyber  security  technology because if it does not,  it will become very vulnerable which could see the complete downfall of  the blockchain and crypto