No quantum computer has yet beaten a classical machine on a commercially valuable task, with the field still stuck in the noisy intermediate-scale era despite billions in investment.
Error rates of roughly 1 in 100 to 1 in 1,000 operations—versus about 1 in 10^17 for classical processors—and fragile coherence times force today’s systems into short, shallow circuits.
Fault tolerance remains expensive: one logical qubit may require hundreds to thousands of physical qubits, meaning useful machines could need millions as wiring, cooling, control and manufacturing bottlenecks compound.
Software also lags hardware, with few proven high-value algorithms and immature tools for programming, debugging and compiling circuits onto constrained devices.
The workforce adds another brake: the sector had about 16,500 professionals in 2025, while 50% to 66% of openings go unfilled and roadmaps still place early fault-tolerant systems in 2028-2029.