I think the more complete and critical answer is from @FuzzyChef.
I think it captures the essence of the problem.
Some more details should be added regarding what's the situation here in Italy. Disclaimer: I'm an Italian living in Italy and I like good cuisine, but I'm not nearly a professional nor a gourmet*.
What you call "prosciutto" in USA here is called, more specifically, "prosciutto crudo", especially when one wants to make a difference between "prosciutto crudo" and "prosciutto cotto", which are fairly different products. Note that "cotto" means "cooked" in Italian, but, as I said, "prosciutto cotto" is not "prosciutto crudo" that has been cooked!
There is no single "DOC" prosciutto (crudo) in Italy. There are a couple of high valued, "DOC" types (very expensive): i.e. "prosciutto crudo di Parma" and "prosciutto crudo S. Daniele", which are somewhat similar products (to a non-gourmet).
But there are also a metric ton of quality types of "prosciutto" made outside the typical areas where "Parma" and "S.Daniele" are produced. The biggest difference is an higher percentage of salt employed during the seasoning. Often those kind of "prosciutto" are called "prosciutto crudo nostrano" ("nostrano" means "made in our area/region") and they cost less than "Parma" or "S.Daniele".
Prosciutto crudo is used in recipes where it ends up being cooked (e.g. Tortellini alla Bolognese, where it is used in the filling), but often you don't use the highly priced "Parma" or "S.Daniele" for that.
As for "pancetta" and "guanciale" they are lower price products here in Italy, because they are meant to be used for cooking, although you can definitely eat "pancetta" raw. It is a very fatty product and also very tasty, and a "panino con la pancetta" (sandwich with "pancetta") is very yummy (and a calorie bomb)!
Keep in mind that in Italy we have probably the most strict legislation against food fraud in the world. In particular, we have an entire branch of one of our national police forces (Carabinieri) who is devoted mainly to prevent and repress food frauds: they are the NAS (Nucleo Anti-Sofisticazioni).
This means that it is very difficult here to be sold "bad food", since an inspection from the NAS finding, say, a restaurant or a food shop selling expired food or (worse) bad food can cause the immediate closure of the business (until further investigations or trials), even if no-one of the customers felt sick!
All this to underline that what you eat in USA and it is sold as "pancetta" or "prosciutto" may not be what we in Italy exactly would expect. We have a huge problem of fake Italian products sold in every part of the world (even worse outside EU), especially where there are customers rich enough to pay a bonus for original Italian stuff (USA, Canada and Australia, for example).
Bottom line: if you buy traditional Italian food in the USA, be sure your shopkeeper sells you legit products, otherwise all bets are off whether or not the products are even remotely the same as the "traditional" ones.