There was a lot more that went into that 30 hours than just the illustration work -- I didn't elaborate in order to remain concise. And although I do keep a local copy of C4D for doing complicated extrusions and lighting for typographical work it, I am much more comfortable working in the vector environment when I illustrate and, quite honestly, I can't afford the time nor extend the mental capacity to learn modeling any further than what I've learned for my specific needs.
It's taken me years to become a competent developer and illustrator; if I do end up needing something done in 3D, I'd like to leave a little meat on the bone for the guys that have spent years learning NURBS modeling and animation.
A more whimsical answer would be that I love what I do, I love to code and draw pretty pictures; I don't love modeling, and I think my disinterest in the medium from an artistic perspective would end up coming through in my work. I assume some of the other professionals would agree, at some point it's not a great idea to extend the time and resources required to pick up other skills, skills that -- like 3D work in my case -- simply won't be used enough in my workflow to justify that time/mental investment
