Even in today's society meat is seen as a key ingredient to use in cooking and has been a part of our diet for as long as we’ve been on this planet. However, what our bodies require isn’t specifically meat, it’s the iron and protein they provide us.
There are countless ingredients at peoples disposal to add flavour to food without needing meat to be a centrepiece at the dinner table.
Preservation has only increased with the invention of the refrigerator. There are countless other techniques dedicated to giving food longer shelf life and giving simple ingredients a bigger punch of flavour and umami to make them delectable. Things like canning, salting, pickling, and smoking just to name a few. Farming has also increased allowing for bigger and better crop yields so people aren’t lacking in options for food.
With such things at peoples disposal they do not have to solely rely on the food they raise and produce themselves, they can forgo eating meat and live on a plant-based diet.