Given the ever-increasing effects of climate change, I think it's likely that access to water will be a huge issue as this century progresses. Wars might even start over it. You look at somewhere like Egypt and wonder what would happen if some of the countries upstream started using or diverting more from the Nile, particularly as they grow in population. You look at China and the effort it puts into acquiring and holding Tibet - which is the source of the biggest Chinese rivers - and you wonder what would happen if India, also growing in population, decides it needs more of that Tibetan water...
If commercial fusion power does become possible, then maybe it will be used to resolve the issue of water shortage by providing cheap green power for water desalination plants... These plants already contribute to global warming, and likely will make the problem even worse as they expand in use due to water shortages. So with the way the world is going, if fusion does become possible, I'm not sure governments will be able to hold it back for themselves or even charge excessively for it - as energy demands and resource demands increase, providing access to fusion power may be one of the only ways to avert war.
Water is a big problem and whats worrying is most of the water around the world is privately owned and if a water were to break out these private companies could be bought out in an attempt to harm the civilians and cause unrest in that country. I might actually start a thread about water consumption and the worries if a war broke out but at the moment I'll continue discussing the quantum computers as this is possibly some of the best discussion I have participated in relating to it.
Bare with me with this reply has I've been working on it for a while and have dropped it and came back to it a few times over the last few days. Its also taken me a while to get this all down. This discussion actually prompted me to log in to the forum after a while because this quality discussion is a rarity these days on this forum.
Holy crap! I did not know we had this many people who are knowledgeable in the quantum mechanics field and can discuss quantum computers in such depth. I'll admit that what you have mentioned about factoring and how its actually done is a little over my head currently as I'm only dipping my toes into quantum computers. My knowledge is limited by I know what factoring is and I know quantum computers are exceptionally good at it but that actual specifics of working it out is still gibberish to me but I appreciate the input on the actual solutions and working it out!
The quantum resistant ledger has been running roughly a year and AFAIK as received some excellent praise and has received a lot of media coverage because of that although your point about reusing addresses wouldn't be sufficient in my opinion because we are then relying on the chance of the address not being targeted rather than implementing a system which is completely quantum resistant. It is true that the less you reuse an address the less exposure it has on the public ledger and thus the less likely it is to be a target although this doesn't completely prevent the address from being targeted due to it still being recorded on the address once they receive an amount. By implementing a quantum resistant algorithm we at least prevent this sort of attack from happening and there is no risk whatsoever although I would agree that reusable addresses shouldn't be a thing and you should only be able to use new addresses every time for other privacy issues but the way its implemented into the blockchain right now is the user gets to decide what sort of piracy level they are comfortable with which could possibly be the best approach if we are to stick with the decentralized way of Bitcoin and not limit users of it to specific rules.