But even if the market is saturated... is it really? I'm just an armchair expert in this case, but as far as I'm aware, there's not a coffee maker yet in every house; they will eventually break if overheated for example (I broke mine's rubber seal by putting it on the stove without water); and there's plenty of untapped markets out there yet.
That said, one person may buy one coffee maker and never need another one for the next decade or two, or pass it on to their children if it's really good. So what another comment said, them expanding into selling coffee as well for example, sounds like an idea.
If the rubber seal is damaged, you can simply replace it, you don't need to buy a new coffee maker. When people mention that newer coffee makers are cheaper and lower-quality, that's probably Bialetti trying to reach a larger market. I guess lots of people bought one and rarely if ever used it (I think even I have one somewhere, but don't ask me where).
As for expanding into selling coffee: that's natural for systems like Senseo or Nespresso, where you have custom pads/pods which you insert into the machine (not sure if third-party pad/pod makers have to pay a license fee to the "system provider"?), but Bialetti coffee makers work with any ground coffee. Might be an idea nevertheless, but not sure about the odds of success - I imagine most Italians already have their favorite brand of coffee and wouldn't suddenly switch to "Bialetti Coffee" just because they say it works best with their machines.
That said, one person may buy one coffee maker and never need another one for the next decade or two, or pass it on to their children if it's really good. So what another comment said, them expanding into selling coffee as well for example, sounds like an idea.