Changes in society have resulted in numerous changes in the food service industry. I'm not sure what you are defining as being included in the "modern" time period, but let's think about some of the diversifications that have developed.
The invention and popularization of the automobile changed society on many levels. People could - and did - travel more, people could - and did - live further away from work and service locations, people could - and did - spend less time at home because of the above. One accommodation to these changes was the development of fast food, first presented at drive-through restaurants designed for delivery of the food through the car window. This impacted menu design, food preparation techniques and equipment, presentation of finished products, and advertising. Another change was the development of prepared foods that could be served at home with much less time spent cooking or baking. Obviously, the advent of microwave ovens was another change.
Demographic and social changes have contributed to the diversification of the food industry by creating new consumer groups with their own disives or needs,some consumers may frequent a particular restaurant because its chef or owner is a celebrity or the restaurant is riding high on a crest of fad or fashion most consumers choose a restaurant whether it be a fast food or dinning restaurant place because it provides quality food at a cost they are willing to pay. and it is most important conribution to diversification this food service industry because people has no time to make food in home every one is working and making money.