As a restaurant consultant I feel somewhat obliged to defend my industry. I am familiar with Russian market, but I think that fundamentally US and EU are not that different.
The problem with Peter's arguments is that, while being mathematically accurate, they do not represent the real picture.
Restaurants are actually pretty awesome business if you treat them like one. It's just that 95% of restaurateurs don't. But those 5% who do do pretty well.
What I do for a living is help people with the transition - I help them establish metrics, collect data, make data-driven decisions e.t.c. As painful as these changes are, they are also very fruitful, and once treated like a proper business almost any restaurant can become succesful, having nice margins and turning profit.