I don't think that there is one standout answer in my opinion, but I believe that many factors lead to overconsumption of meat. Cost and availability are big factors, in my opinion. Meat is often cheap, and available in large quantities. Quality doesn't seem to be as much of a concern- especially with consumers in big box stores or discount retailers. I also believe that there is a comfort for many Americans when it comes to cooking with and eating meat. They are familiar with the products/dishes, like the taste, and don't feel the need to try anything different. Plant-based dishes are just as easy, cheap, and flavorful, but it can feel daunting when you aren't familiar with ingredients or recipes outside of your comfort zone.
When I think of "American values" and ways of life, I do see all all of those sentiments reflected- cost-driven, comfort-focused, "more bang for your buck". I think that Americans are also hardworking and inventive, so I do hope that more folks try to branch out, learn more about plant-based foods, and eat less meat.