I've been exploring making my own salami and have learned that it is a lot of work! Not only must you make sausage, but you must also ferment it and dry it for many days. The fermentation piece seems especially tricky due to the work involved with fermentation starters and the risk of illness (or even death) if done improperly. The fermentation and drying periods also require fairly precise humidity and temperature.
This is why I'm surprised to see so much salami and peperoni in grocery stores. You can find these everywhere for very cheap, which I find surprising given the amount of work involved. I suppose it isn't that expensive if done at an industrial scale with meat scraps, but still, I have doubts that all salamis in the USA are indeed fermented.
Salamis are by their definition a fermented product. Are all or most salamis sold in the USA indeed fermented?