Quantum computers will always exist as a coprocessor, like a GPU or an NPU. You cannot run an operating system on your GPU either. Your GPU is worse for a lot of general purpose tasks your CPU can do, but it excels at very specific kinds of tasks, and so your CPU delegates those specific tasks to the GPU. That is how quantum computers work in practice, they are never stand-alone computers. They are always attached to a classical computer that delegates tasks to it. They won’t ever replace regular computers. Even if in the distant future they manage to build quantum optical chips that run at room temperature at can be made consumer-affordable, they will just be sold as QPUs which you would install into your regular personal computer if you need one.