Diners were a quintessential part of American culture in the 20th century. From the 1920s to the 1940s pre-fabricated diners, which were essentially entire restaurants inside railcars, became big business for both companies selling them and individuals buying them as an affordable way to break into the restaurant business after World War II. In the 1950s and 1960s as more people took road trips in cars, diners became an essential part of eating on the road. Fast food restaurants largely diminished the number of diners on the road in the 1970s, but if you travel to the Northeast, you can still see lots of diners in New Jersey, New York, and the New England states. Red vinyl furniture was, of course, commonly in use throughout these diners. These sofas are known as “booth seating” or “banquettes”.
Sites like Alibaba sell exact replicas of the classic diner sofa at wholesale. If you're planning to start your own IRL diner or just want some unique seating for your breakfast nook, you can buy a high quality banquette there, although be prepared to negotiate a reasonable price on shipping.