Quantum computers: why Google, NASA and others are putting their chips on these dream machines

Considering the immense challenges to building quantum computers, I'd say we are roughly where we were in around 1970 with classical computers. We have some quantum computers, but they are still pretty unreliable compared to today's standard. We call them NISQ devices - Noisy Intermediate-Scale Quantum devices. Noisy because they are pretty bad, and intermediate-scale because of their small qubit number. There are a few public quantum computers available for anyone to programme on.