But content does need to be there from the beginning.
Content vs. web-design-elements-that-aren’t-content is not a chicken and the egg argument. It’s not about evolution. It’s about genetics.
Which came first, your mother’s genes or your father’s genes? Silly question. You need them both in order to be you.
Same with content and the other elements of web design: Content is a vital part of web design. Design, by all means, from the content out. Don’t shuffle content to the end of the design process.
(Content first vs. content from the beginning: Is it semantics? Maybe. But it matters. I’ve seen a number of people who interpret “content first” as “you need final copy before the designer can start working,” which is wrong. And claiming firsties is the kind of behavior you expect from blog commenters, not web professionals.)
Content needs to be there from the beginning. But it doesn’t need to come first.