Is it possible for a blog to become profitable by selling advertising AND paying staff writers when I, myself, don't blog? Or is it just futile to expect that advertising would generate more revenue than quality writers?

Yea that's possible but you need decent subject to attract advertisers. I know some of the blog owners making huge profit through blogging.

The blog needs content as well as advertisement itself for people to know about it.
You could start with search engine submissions,
and or mailing lists.

Well what I mean is running a business by hiring staff writers and generating a profit off of their blog entries. Not my own blog.

You can do that as well but you need to attract advertiser through your blog content and popularity, however i would be more interested to make a blog popular and sell it out and start another with different subject...