You are guilty of blinkered vision.
Portsmouth FC has a history of over a hundred years,which I am sure he will have had researched for him,up to and including last years FA Cup.
The stadium has had planning permission granted,but Abramovich did not proceed (presumably due to the recent credit crunch),however to say that there is no room to expand is not correct,(that also includes plans for a new supermarket etc,etc ) and there is always the land outside the Portsea Island area,such as Cosham,Farlington,etc,etc.
Whether it is "an awful city", is just your view, but many hundreds of coaches take holidaymakers to Southsea every year, and many more go to see all the other attractions, and I would suggest that an Arab billionaire could easily see the advantages of Portsmouth.
BUT,BUT,BUT in the end he doesn't give a flying fig. All he sees is a team in the Premier League as opposed to one on another planet somewhere.