Drupal is just not ready for the mainstream.

http://www.whitehouse.gov/
http://www.theonion.com/
http://www.fastcompany.com/
http://www.wfp.org/

ORLY?

*cough*

I'll agree - Drupal does have a steep learning curve. With regards to theming/styling, though, it's no different than any other CMS. Designers will have to fight cross-browser css compatibility issues with whatever CMS or template engine they're using.