“We expect that within a few years, sufficiently powerful computers will be available” for cracking blockchains open, said Nir Minerbi, CEO of quantum software maker Classiq Technologies.

Here is my source: https://www.cnet.com/personal-finance/crypto/cryptocurrency-faces-a-quantum-computing-problem/

There are countermeasures being taken place now of course to keep security up which is standard for the cybersecurity community of course. However, even now, people are still losing their accounts to simple social engineering tactics.