Were you disappointed with the coffee you were served at your favorite restaurant?
You had a great meal, but what you remember best is the mediocre to horrible coffee you had at the end.
A few years ago the answer would simply be that they probably did not know better. While the chef took great pains to source the best food ingredients he could, coffee was considered a generic item, like sugar. "It's all pretty much the same." Today however, even non-coffee drinkers know that there is a wide variety of great coffee available.
So, why is it so difficult to get a decent cup at most restaurants?
In large part it is due to the "cell phone" effect. AT&T, Verizon, Sprint, give you a phone for free or discounted, and you agree to buy your monthly service from them. The service might not be great, but you got a wonderful deal on the phone. Plus, there is a lot of aggravation and cost involved in switching, so you stick with it.
Coffee Roasters with big budgets have been using this business model to sell to restaurants. Your favorite place gets its brewing equipment for free, and in turn agrees to buy all its coffee from that roaster.
This has two primary implications, neither of them good for you as a customer. First, the smaller, higher-end roasters don't for the most part have the economic muscle to give away equipment. Second, the large roaster either doesn't sell the quality coffee you enjoy, or has to substitute a lower quality bean to the restaurant in order to recoup their equipment costs.
When will this change? Only after enough customers speak up and let their feelings be known. Tell the chef you loved your meal, but had to pass up his wonderful desserts because the coffee was so bad. Send an email, maybe with a link to your favorite local coffee roaster.