I think that, in today's market, searching for help with "SEO" is more than likely to get you those results posted by OP. As tedster discussed, those will be the groups offering outdated services.
Nowadays, I think it's wiser to look for an agency that integrates SEO into more serious marketing services. So, searching for a "web marketing agency" or something along those lines, will be more likely to get you to the companies with a more "mature" approach to SEO.
On in-house vs. outsourced SEO, I think nothing can beat having an in-house SEO or SEO team - all abilities being equal. An in-house can react faster and will have more at stake that your business succeed. I think it can be more difficult to find an in-house that is the right fit versus an outside agency.