The problem is that HRT is looking more and more like an empty shell. From what I’ve read across the web, their buildings are leased, they’ve laid off a lot of staff, including the ones designing the 2013 car, which would probably be miles off the Toro Rossos. I’m pretty sure the FIAT group has other things on its mind as well, with the American market for instance, F1 wouldn’t do that much good.
Fiat F1 might sound nice, but does Fiat really need a team that struggles to get to the 107% in Melbourne, when Fiat cars are just getting rid of their old reputation of slow, unreliable cars?