Ask HN: What do small marketing agency deals look like?

I can't figure out the math behind all of these smallish marketing agencies. In my city there are at least a dozen of them; 10-20 employees, very nice offices, they typically have one or two Fortune 1000 clients, some smaller clients, and a few local clients. They seem to launch one or maybe two projects a month. Projects are usually some mix of creative video and photography, a microsite, social media creative, digial ad creative and buys, content, "brand strategy", etc.

It seems most of them would need to bring in at least $100k/month to break even. Are the deals that big? Anyone have examples of number breakdowns for these types of deals?