Quantum Resistant Bitcoin?

What will happen when a hacker, armed with a quantum computer, begins quietly breaking the encryption of the Bitcoin network and stealing coins from owners accounts?

Sound farfetched? Today's quantum computers can solve problems in less than one second that it takes a classical computer one week to solve. China, Germany, Canada, India, Japan and the United States are racing to develop quantum computers many times faster than first generation quantum computers.

Eventually Bitcoin holders will figure out their accounts were hacked. What then?

One trillion dollars of Bitcoin value will go up in smoke?

Or will the Bitcoin network save itself by transitioning to Quantum resistant cryptography?  That is the scenario proposed in "Committing to quantum resistance: a slow defence for Bitcoin against a fast quantum computing attack" a paper by I. Stewart, D. Ilie, A. Zamyatin, S. Werner, M. F. Torshizi and W. J. Knottenbelt published by the Royal Society.