It depends on what we mean by "slow progress". The physical implementation of a quantum computer in silicon was proposed in 1998 [0] and a two-qubit gate was re

It depends on what we mean by "slow progress". The physical implementation of a quantum computer in silicon was proposed in 1998 [0] and a two-qubit gate was recently performed on it. This is in contrast to the ion trap quantum computer, where a two-qubit gate was proposed and performed in 1995 [1]. On the other hand, superconducting quantum computers followed the same road that silicon is on right now. It took a couple of years for superconducting qubits to be robust enough to perform universal quantum computation, but it's progress has accelerated in the past couple of years. So this says nothing of how fast silicon quantum computers will progress in the future. [0]: https://en.wikipedia.org/wiki/Loss%E2%80%93DiVincenzo_quantum_computer https://en.wikipedia.org/wiki/Loss%E2%80%93DiVincenzo_quantu... [1]: https://en.wikipedia.org/wiki/Trapped_ion_quantum_computer#History_of_trapped_ion_quantum_computing https://en.wikipedia.org/wiki/Trapped_ion_quantum_computer#H...