Coming from a smaller city in Florida I was surprised at how many cash-only restaurants there are in Berkeley, I mean, it's the Bay!

Granted, Berkeley seems to have its own notion of what it's culture should be and people don't seem to mind paying cash only. I think it's important to realize that you are projecting your own expectations onto other people's products, and in their minds they are perfectly happy losing your business so that they can focus on cultivating the kind of customer base they want.

Take Starbucks as an example of the opposite extreme, they take credit cards, drive thru, have uncomfortable chairs and loud music to discourage seating all in the effort to move as much coffee as possible. Starbucks does pretty well, but it's probably in this guys best interest not to try and copy Starbucks.