On the surface, your argument has intuitive merit. However, youtube isn't a business unit. it's a subsidiary.
http://googleblog.blogspot.com/2007/01/look-ahead-at-google-...
http://news.cnet.com/8301-10784_3-6153267-7.html
edit: sorry, that was sorta snarky. and things may have changed since the viacom lawsuit. (it was a subsidiary in late 2008)