Is a season with Joey Barton not woth 4 million?

The way i see it, Barton running down his contract is a win-win:

The cost of replacing him would be 5-10mil, which would be much more than a years extra wages or whatever he wants, so faced with the choice of losing him for nothing or giving him the contract he wants Ashley would probably offer the contract as it's the smarter (cheaper) option. If he does leave after the year is up he shows the fans he appreciates us and the club by not bailing on us, and sticks it to mike ashley (for bonus points). On top of that, he can then get a better contract at his next club, since there won't be a transfer fee.