I don’t visit buffets with frequency, but I believe I’ve been to a sizzler, vegas, and reno buffets which all had soft serve. I went to an Asian buffet restaurant that did not offer soft serve - only individually packaged cheap ice cream. the Asian buffet was the least expensive buffet that I have ever visited. It was mostly Chinese food and sushi with a few American classics but I had a good experience there.

I don’t think I’ve ever been to a buffet that has not had a soft serve machine