In Japan, proper sushi is only eaten at sushi restaurants. Izakayas and other casual restaurants (such as hotel restaurants) may offer a small selection of nigiri sushi or rolls, but it is not the "real deal" so to speak.

At sushi restaurants, a meal will usually include various "tsumami," such as small grilled fish or shellfish, crabs, makimono etc... but the focus is always on the sashimi and nigiri sushi. These restaurants do not offer "alternative" menues for those who don't want to eat sushi.

Sushi is only one kind of Japanese food, and most people in Japan do not eat it very frequently. Additionally, there are many different types of sushi, and sushi chefs often offer their own renditions of various items (as opposed to offering strictly edo-mae sushi, for example). In other words, endless variety is possible.