Why Tokyo Succeeds
It would be a gross understatement to say that there are lots of restaurants in Tokyo. Gigantic portions of the culture here are food-based and there really is no better place in this part of the world to eat such a wide variety of food.
Thinking about owning a food-based business where we live is (or appears to be) difficult. The distances between cities and even neighbourhoods is great compared to a densely packed city as Tokyo. Even San Francisco is spread out enough to make it a chore (albeit a happy one) to get to a restaurant...
...Tokyo succeeds because of it's sheer density. Buildings, people, neighbourhoods... I am positive that other cities are like this as well but since I spend 7-10 days a year here, I keenly notice food here.
As with housing, location is nearly everything. Foot traffic is probably best because there is the impulse factor of seeing food and wanting to taste it now. By foot, train or subway, nearly everywhere is a good location here. The restaurant density near train stations is astounding and often on a multi-story basis. A seven story building? It's not at all odd to have restaurants (or bars) on 5 out of the 7. Now take that to a BLOCK of tall buildings and you get the idea of just how many...
Even in the outlying neighbourhoods, the local restaurant is ever-present (along with the convenience store ("conbini"), the housing office and other necessities) offering traditional and modern food. Most of these places are small and inherently intimate. For example, a mere block away from my temporary apartment here is a yakitori place, an okonomiyaki shop, a small bar (specializing in wine) and a sushi shop. I literally walk 50 feet in two directions and have many nights of food chioces. And this is in a *residential* neighbourhood!
For anyone who really wants a unique food experience, Tokyo is your place. Your choices are limitless.