I realize that since content marketing is (or can be) a part of SEO, then it would logically follow that it's up to whoever is doing the SEO to create the content*. And when it's 1 person or a small group of people that work for 1 company, doing its SEO, that makes perfect sense. But I'm having a little trouble wrapping my mind around how that's supposed to scale up for an outside agency responsible for the SEO of 5 or 10 or 50 other companies.
One of the biggest factors in my misunderstanding of the system is the reasoning for creating content in the first place. I absolutely understand how a professional in some field (let's say dentistry for example) could write up some insightful, accurate blog post about why flossing is great. After all, a dentist does (or should, hopefully) have a level of expertise on the subject that most people don't have. That blog post is a tangible addition of value to the website for anyone curious about the subject.
But why would anyone want to read a blog post about wisdom teeth written by just some random person at a marketing company? If that person has the time to do a lot of research and BECOME something of an authority on the subject of dental care, then that's fine. But what if they also need to create content for clients that do plumbing, car repairs, and cooking? I don't really see how someone can become enough of an expert on enough subjects and still have any time to do the other parts of their job. Maybe I'm just expecting too much, but I sort of feel that the internet is already full enough of advice and information from people that have no idea what they're talking about, so content from someone that's not an expert (but is a marketing person that the expert hired) seems... frivolous to me.
So to get back to the actual question, should/can an SEO ask their clients to create at least some of their own content, or is it the SEO's responsibility to generate all the content, even if it's not always stellar? Or is it just one of those "Could God make a rock so big that he couldn't lift it? Yes, he could, and then he would lift it" (or however that saying went) sorts of deals?
Thanks for the feedback, this can all be kind of overwhelming for me at times.
*"Creating content" in this specific case meaning writing blog posts, making videos, etc.