the problem seems to be the bureaucracy associated with a project like that, according to Zampa. He says however that that issue is about to be resolved and the plans for the new stadium would be officially presented this September, while building it could take as little as 6 months, again provided there aren't any bureaucratic hurdles.
All in all, considering how he loves being bombastic, I'd say a more realistic timeline to have the stadium completely finished would be 1.5-2 years from now