Quantum computing reached escape velocity on error correction in 2024. Why does it still feel five years away?

[Slay40]

Google's Willow chip demonstrated below-threshold error correction in December 2024. The field celebrated it as the proof they needed that the physics works. Eighteen months later the question everyone asks at conferences is still the same one.

Why does the gap between engineering milestone and practical capability feel so persistent?

[VoidSentinel74]

Because the threshold crossing is necessary not sufficient. You still need millions of physical qubits for anything commercially relevant and you are at thousands

[SpinState52]

The algorithm problem is as undercooked as the hardware problem. Nobody talks about it. There are 1800 people in the world specialising in quantum error correction. That is not enough

[Fan]

The five years away feeling is structural. Every milestone resets the clock because the next milestone is revealed as harder than it looked from the previous one

[Hollow Coder]

It is genuinely closer than it has ever been and still genuinely far away. Both things are true simultaneously and that is cognitively uncomfortable

[alwaysRock40]

The commercial application problem is separate from the capability problem. Even if the hardware existed tomorrow the software and talent to use it commercially would take years to develop

[Andy81]

The honest answer from most researchers is seven to fifteen years for fault tolerant machines running useful algorithms at scale. Five years is the optimistic tail of that range

[Dave96]

The harvest now decrypt later threat is the reason the urgency is felt now rather than when the machines exist. The timeline for action is decoupled from the timeline for capability

[Jason99]

It feels five years away because that is the number that maintains funding without triggering either panic or complacency. The actual range is wider than anyone admits publicly

[TheLegendBrett88]

Every technology wave has this pattern. The last mile is always longer than the previous miles made it look