Make the case for why quantum isnt going to be a problem

Please understand that I am looking for good faith discussion. I think decentralization hurts when it comes to updates. Going to be hard to update quickly (unlike at a centralized corporation where they can just roll it out). Also - why would the first quantum-resistant algorithm work? I think it is likely that it will take a while for a mature quantum-resistant to come into existence. SHA256 was not the first algo of its kind, it took decades to get there. So not only is bitcoin going to have to update, its going to have to update a bunch of times. As the algos mature, they might be vulnerable. I just dont see the process of updating the encryption mechanism a bunch of times going smoothly considering the nature of decision making when it comes to bitcoin. What am I missing?