First of all, I'm really good at SEO, but I'm never going to make a "top SEO company" listing. First because I don't care. Second because .. no, actually, it's just that I don't care. I've been there. I didn't like it. But since you ask, let's take a look.
Let's start with .. it looks like I underprice myself. Might be a Yorkshire thing. You'll be paying £60-£120 per hour on average for SEO through a 'normal' SEO company, and anything upwards of £1,500 per month. It's still a fraction of what people are paying for advertising so it really shouldn't be an issue at all.
And although most top SEO companies segment out their services .. so if you want link-building that's like an extra module you have to bolt on top along with a raft of other add-ons .. most don't seem to consider themselves content agencies, and most don't have much in the way of graphic design. I'm with them on the latter point, I love it but I'm no good at it. But content? That's .. part of SEO, I don't see how you can't connect the two.
So although clients may wish to just outsource the problem away, SEO companies seem to be just SEO companies. It's like it's for the client to work out how to co-ordinate SEO with advertising, social, graphic design, content and the rest. I'm sensing nightmare meetings.
My thing is: I build systems. I'm interested in the customer journey from having never heard of you to becoming a bonkers advocate. I want to get in the customer's head and see all the touch points, all the messages, and line them up, get it all to make sense, then optimise the bejeesus out of it. SEO is part of that, but digital marketing is multimodal so I'm a little confused how you can do SEO without getting involved in content, social, pay per click, email marketing, the website, the app and so on.
Like I say, I'm not a top agency, I'm a freelance SEO specialist so I'm probably doing them a disservice, I'm just reporting what it looks like from the outside.
If you fancy a chat, pour your co-ordinates into this boring old form and I'll reply.
(Here's a broader view on SEO companies.)