I never find the ability to visualize things, or imagine voices or sound, too interesting, as I have never used those abilities to do anything practical. I do not rehearse words in my head before talking, or create an image in my head before drawing art. Doing art teaches you that you only have a general sense of what a lot of objects look like. People need reference for almost everything they haven't drawn before, a…
You are hopefully aware though that this is not the norm. Many (if not all) artists tend to visualise their work before and while they are doing it.
People have processes they go through to eventually get to something reasonably correct. Systems for drawing people, perspective rules, etc. These get extremely elaborate. They shouldn't need any of it if they could fully visualize the scene. They'd just need to copy that image to paper.
You'll hear people say things like "trust the process". They are struggling with what they're drawing looking wrong to them, until they're fairly far along and the shapes are fairly complete. Even when they're doing things correctly, their brain isn't recognizing it.