Indeed. I'm still surprised that there aren't any cafes right near me in San Francisco who have free wireless (if I'm wrong, lemme know: 21st and Valencia—I only know of Maxfield's, which is a bit of a haul). In fact, there aren't any that have paid wireless—even though many of them offer Internet access via their own machines, in which case they're already paying for the DSL line.
I suspect this is mostly just a lack of knowledge on what it takes to get set up. This is the reason I suspect many shops go through networks like Surf and Sip, which can't possibly make them any decent amount of money, instead of just giving it away and making more on the extra food and beverage sales. The benefit is, Surf and Sip comes in and turn-key's it for you.
Then again, some coffee shops probably don't want unsocial geeks sitting around staring at their laptops all day.
On the plus side, I went to my old neighborhood coffee shop today, with the plan of paying the Surf and Sip $5 one-day rate, and lo-and-behold, there was another free network available. Yay. (I wouldn't invest in Surf and Sip.)