"Four people" is an exaggeration intended to be humorous. The more straightforward way of saying it is: there is tremendous market demand right now for this skillset. This skillset is extraordinarily uncommon irrespective of the demand for it. Additionally, market conditions currently offer many independent, extraordinarily attractive options to individuals who possess this skillset. Three options, among many, include being a) extraordinarily highly compensated at a Fortune 500 firm which is capable of being arbitrarily generous to retain their services, b) using their skillset to found a startup, or c) forsaking full-time employment and instead consulting for numbers which would make your head spin. There exist other options, too. This means that the number of people in the (already small) hiring pool who are actually available for hire is even smaller than you would otherwise assume.

My advice about the landing pages is in more depth on my blog in multiple places, but basically, "Build a CMS to spit arbitrarily high numbers of landing pages out of some data source which you have and some templates. Iterate on the templates in a data-driven fashion." It's essentially as technically complex as the Rails 15 minute build-a-blog demo. For more elaboration, see blog.

what's your opinion on building automated computer-generated content from data you own (trends from stats, etc). Isn't that frowned upon by Google?

That's an oversimplification of Google's approach to mass creation of pages vis-a-vis organic SEO. Google will let (many) pages that would never appear in the main results appear in AdWords ads as long as one's credit card doesn't get declined. (There are things Google disapproves of in landing pages, but "having lots of landing pages" is not one of them.)

Do all these landing pages live on the primary domain or are they spread around different domains?

OK, so what about auto-generating pages that you intend to rank for organic search, NOT to advertise in Adwords? Do you think this should never be done? Or are there scenarios where it's gray-hat, but you figure it's safe to do?

You can always throw in some noindex,nofollow tags on the landing page to prevent Google from indexing them.

You could also consider using canonical tags for landing pages that are slight variations of each other [to prevent duplicate content penalties]. This one is really just a guess.

I thought you had some lady who writes your landing pages for you. Have you got it totally automated now, or am I confused?

Content for the website was written by freelancers, yes. It all sits in the database. My AdWords landing pages repurpose a subset of the same data with different templates relative to the (publicly exposed) content.

Four people is just an exaggeration. He's saying there are very few people who are genuinely great at this stuff.