My thought about Photoshop artists are:

- They have a lot of training, so they know their tools better than we do.
- They also have more training in drawing in general, on paper etc, so they are used to projecting 3D ideas onto 2D in their minds.
- They have Wacom boards.
- The artwork is their work so they put much time and effort into it. And patience. They try and try again.

I have worked together with Photoshop professionals, and they can whip up nice things in no time using tricks I never knew existed, but they also fine-tune details, almost at pixel level.

So their "magic" is very much training and spending time on the tool. At least from what I have seen.