The media is being super misleading about quantum computers and who has the edge, who is "winning", etc. They are a very long time away from them being commercially viable or even available, they are still quite large and very expensive, and the software needs to be completely rewritten and everything started over from scratch. Not quite the same thing, but here is a recent image of a scanning tunneling microscope, which is doing quantum research, some of which would go toward quantum computing. Their Wikipedia page has more information. Yes, this is research equipment, but this is state of the art and the related technology would need to get dramatically reduced in size in order to integrate it with quantum computers.

Comparatively, there are billions of PCs and smartphones in use with solid software and spare time and well established networks for contributing towards BOINC projects. I completely hear you, but the technology is a lot farther away than the media gives on.

Even the earliest, most basic quantum computer will quickly make PrimeGrid obsolete, and probably most other mathematical BOINC projects for that matter. Projects like WCG will be safe though I think, there will always be types of computations that are more suited for classical CPUs.

Agreed. The widespread implementation of quantum computers will not come anytime soon, and likely not in the lifetimes of many people who read this forum.