The problem with this suggestion is that the floor that Starbucks occupies costs a fortune. The author says it himself: he'd be willing to pay "a small" fee to hang out in a Starbucks for 3 to 5 hours. If you were to actually look what this space costs Starbucks to rent, I'm sure it would amaze you.
Starbucks isn't your office. Hanging around and having a chat is one thing, but staying for upwards of 5 hours is just excessive.