>> People who drink out are putting on a little display of their wealth, 



Uhhhh, yes.... and no. I've done a lot of business (IT stuff) in coffee shops and bars (yes, I'll have a glass of wine or two :). It is generally less "stuffy" than meeting in an office or cubicle or at a big oval table in a huge meeting room. Oftentimes it increases the productivity of a meeting because the parties involved are more relaxed and more receptive to each others' ideas. 



I would say it's about half "show" and half business in the coffee shops I frequent.