The difficulty is that Fiat just don't know where to go with the Alfa brand. Since Arese closed Alfa has had no "home".
Ferrari have Maranello and Maserati have Modena just as they did before any Fiat involvment and they are still dedicated sites to the brand. Fiat have Turin of course but in the last 8-10 years Alfa have been built at various Fiat plants or assembled at Pininfarina.
The developement costs of Ferrari or Maserati can to some degree be recouped by the high ticket price, (although that hasn't recently been the case with Maserati), whereas for Fiat to develop a new Alfa but still sell it at an affordable price in the mid sector means that it can only be via shared floor pans and components with the Fiat range.
Nothing new there I know, but you can see that they have no incentive to introduce new models into the Alfa range.
The 100 year celebrations were a real indicator of Fiat's stance of the situation as they had zero input into what should have been the marketing opportunity of a lifetime.
Bottom line, they are probably anxious to unload the Alfa brand but know that the true Alfisti would not want to buy a car that was not built in Italy even though the Milan connection is now long gone.
Other successful take-overs have meant that although ownership has changed, there is still production and assembly in the country of origin, the only way this could currently be achieved is via a shared deal with Fiat which would not be a clean break for the new owner.
The ideal scenario is that Fiat have several new Alfa projects "close to their chest" which they have yet to disclose, but I doubt this is the case.
If they have, they will probably be Fiat/Chrysler rebadging of various multi-air templates.
I can't really imagine another manufacturer being able to successfully revive the brand, but let's hope that somewhere, there is a positive future for the Alfa brand.