The suggestions that quantum computing could kill bitcoin are made by people who don`t know anything about quantum computers or the blockchain.
I think that the human civilization would need decades to make quantum computers cheap and available for the majority of people.I don`t see this as a threat,perhaps this is an opportunity to improve even further all the crypto technologies.
In other words, you're saying that the scenario that would make this threat possible will arrive in mere decades? Even the brightest minds often fail to correctly estimate how quickly home computers are able to advance.
Here's an article about very smart people who knew a lot about their field (computers and tech mainly)... and yet made a few wrong calls. Nothing wrong with making mistakes but point is, what's wrong with ideas?