I would argue Birmingham as a City is a factor in this. To call it unfashionable is an understatement. London just becomes more and more dominant economically & socially. As a knock on effect even clubs like West Ham & Crystal Palace are in danger of sailing past us in coming years.
Manchester manages to to act like UK's real second city, has a swagger and confidence that Birmingham somehow lacks. In fact the whole Midlands is a bit of a malaise. Is it a coincidence Midlands football is in the doldrums?