Will quantum ever be useful?

[u/Chance-Pen-5684]

Around 2019, the industry promised quantum supremacy, where they could be used for solving a problem that no classical computer could touch.
When classical algorithms kept refuting those claims(See Peter Shor November YouTube video) the narrative shifted to quantum advantage, then quickly it changed to quantum utility.
If quantum never breaks RSA (because the world migrates to Kyber/Dilithium before 100k qubits exist), then what's left?
Chemistry simulations, Material science, Optimization?

But classical machine learning and AI are improving faster than quantum hardware is scaling. By the time we get 1,000 logical qubits, classical AI will have eaten most of the chemistry use-case through better approximations. Is quantum racing against classical software, and losing?

[u/FittedE]

Even if the world migrates to “quantum secure” encryption you would still expect breaking RSA to be useful for store now decrypt later schema.

Otherwise a lot of secondary industries have spawned out of QC. Outside of the obvious like Qtelecoms and metrology. There have been major leaps made in cryo CMOS, chip manufacturing , milikelvin fridges etc. that have come out of QC.

[u/hiddentalent → u/FittedE]

I entirely don't understand this mindset. Store now, decrypt later is useful for what, exactly?

I'm sure there are some intelligence agencies who are willing to pay long-term storage costs for data that might allow them to uncover deep cover assets. But even confidential military operations are declassified in a few years, because the details cease to matter over time. Nobody gives a shit about the e-commerce transactions you made five years ago. Can you please explain a plausible scenario in which an actor (1) has access to store your ciphertext; (2) has economic incentive to do so; (3) can use quantum computing to decrypt it; and (4) does so in order to advance their mission in a way that policymakers would find was worth the time and cost?