This is an informative article, although I reached the opposite conclusion as you by the end!! Based on all the info you give about Quantum Computing going from 5 -> 16 quibit systems, and that 50 quibits is enough to basically destroy Bitcoin's security... AND it could happen in secret, theoretically.. no good!

Seems to me like something the bitcoin community would want to address sooner than later. "Quantum-proofing" the system may be one of the top 5 "Black Swan" issues to be considered, in my humble opinion.