Wasn't the SHA1 collision limited to PDF documents?
I only quickly read the statement, will have to re-read the document more carefully.
The attack was done on PDF files because that was the easiest to do that makes the collision obvious (clear visual difference, same hash). However, they have shown that it is possible to produce a SHA1 collision in general (a PDF is just a bunch of bytes of data, just like any other piece of data).
Anyways, if someone is able to crack SHA256, they will be using that technology for something larger than bitcoin.
We are talking national security type stuff here: breaking into government systems and decrypting top-secret documents.
The problem is not that QCs can break SHA256 (and they really can't) but rather QCs that can break ECDSA. If someone can get the private key out of a public key, then Bitcoin will need to stop using ECDSA.
Quantum Computing is Science-Fiction and nothing else! One value cannot be two values simultaneously (or switch between the two)! It defies all logic, observable reality and deep down you all know it!
Just because you don't believe it is possible and can't get your mind around the extremely difficult concepts of quantum physics does not mean that it is impossible. Not only have quantum computers been made (low qubit, but still QCs), but the quantum behavior has also been observed.
IBM has been doing a lot of research into Quantum Computers and have also made a 5 qubit QC which people can use.