I don't know, Rob. I spent a lot of time in darkrooms, pulling prints from the dish, and I can't really see much difference between that and what happens on the computer. Given a fully equipped darkroom and enough time, I'd venture to say you can do just about anything to a photograph you can do with Photoshop.
Try to fix spherical aberration in a darkroom...or adjust perspective...or substitute one color for another, but only that color and nothing else...in fifteen seconds.
Painting and photography are radically different; their only common ground is that they're visual. However, people who say they can't draw usually haven't tried hard enough -- most drawing professors will tell you that if you can write sentence with a pencil, you can learn to draw quite well indeed. But it takes persistence and practice and you have to go through quite a bit of time when you're bad at it. A famous artist, Jim Dine, decided after he was already famoius that he didn't draw well enough, and took several years off to learn...and it took him several years to get where he wanted to go. It's like playing the piano -- you're not a good piano player after two weeks of lessons. And that's not necessarily true with a camera. If you give somebody a camera, and two week's worth of lessons (say, a two-week workshop at Santa Fe), that person could probably take a credible photograph, in the technical sense. That doesn't make him Ansel Adams, but, unlike other art forms, the technical aspects of camera use are pretty easy to get.
As for great drawings by children, what you usually have is great drawings by children. If you think your kid has a great talent (and I can assure you that he/she doesn't,) ask him/her to draw an accurate picture of a simple pine cone. Won't be able to do it. That's why drawings by children usually aren't found in museums.
I think it's important to distinguish between facility and talent -- facility is pretty much a matter of eye-hand coordination, and some people have quite a good facility, and some children are better at it than other children. They are not necessarily talented, because talent involves a whole complex of learned qualities, plus a cultivated way of looking at the world. Cezanne was one of the world's great artists -- a great talent -- but didn't draw as well as many contemporaries who were not nearly as talented, possibly because he didn't care about it enough. He didn't have an easy facility, but he did have a great talent.
The fact that a child can sometimes draw better than an older person need not be particularly surprising -- probably the kid practiced more. That's usually the case. If you look at most "prodigies," the thing that really distinguishes them is that they began working very hard at their skill at a very young age. (Tiger Woods, Mozart, etc.) I think one of the greatest gifts you can give a kid is that when they show a particular ability, in which they are interested, to then go out of your way to really *appreciate* what they're doing. The more approval they get for a particular activity, the more they're likely to work at it, and the better they'll get compared to their peers, and this can snowball into real talent; of they eventually go in a different direction, it can nevertheless remain an interesting and serious pasttime for the rest of the kid's life.