While the progress with Quantum Computers has been slow, it has been extremely diverse.
Some of the hardware architectures include:
Sourcing parts for quantum computers is also very difficult.
Superconducting quantum computers, like those constructed by Google and IBM, need helium-3, a nuclear research byproduct, and special superconducting cables made only by the Japanese company Coax Co.
PSIQuantum’s approach with copper based photonics, cooling with liquid hydrogen that is readily available, and redundancy to provide error correction on a PCB for production at scale.
Their hardware is capable of running Shor’s Algorithm, to solve discrete logs and factor integers.
D-Wave Systems has produced a quantum annealing computer since 1999. They use a superconducting niobium with liquid helium based cooling. Their hardware is capable of performing Grover’s Algorithm, solving the traveling salesman problem, querying databases, cracking AES and other computing tasks.