I don't think that bitcoin will die, it will have some value even if some new technology appear, people will collect it cause it's first of it's kind.
Everything around us is evolving, bitcoin will have the same destiny, and I think bitcoin will be only better with the time. Quantum computing is also technology, and why bitcon can adopt on it? For me all mentioned scenarios are lucky guessing, I think bitcoin is strong enough to survive all upcoming problems and threats.
If you meant "adopt" meaning that bitcoin will survive the attack of quantum computers, then it will be because there's an algorithm that's going to counter quantum computing attacks. I wouldn't actually sweat the possibility of quantum computers finally going mainstream since it will be mainly used by other things. Bitcoin is just a small thing if you look at the bigger picture.
"Google's D-Wave 2X quantum computer can solve algorithms 100,000,000 faster than modern computing devices." (
link) There's already a quantum computer and it can easily brute force its way to our accounts but it doesn't, why? Because there are far better things to do using a quantum computer.