I think drawing and painting is a lot more accessible than sculpting, or at least it appears to be. You can just grab a pen or pencil and doodle and get drawing things but it's not as easy if you wanted to sculpt something. I personally prefer looking at drawings and the shading/colour etc. I prefer seeing art on paper than anything a bit more 3 dimensional :)
I think drawing/painting is less expensive (initially) and its easier to get into since you just need a pencil/pen I also think its harder to think three dimensional so not that many people go there creatively
In the art department at my college, sculpture is just as popular as drawing/painting. A few months ago we got to meet Peter Callas and he spent the day lecturing and doing demos and stuff which was pretty cool.