The reality is (with the exception of United who are in a different league in terms of manager, revenue generation, brand and where they started) that the takeovers that succeed are only the ones where thethat people taking over have the money that a) they can afford to blow the game apart financially and out compete anyone (Walker, Abramovich and now Mansour did that) b) they can afford to blow a lot of money and not go bust if they do and c) they can do this out of spare change and not have their life effected if it doesn't work.
When Walker did it being worth a few hundred million was enough now I would say to really make a dent in football you have to be a multi billionaire who like ROman or Mansour can happily throw half a billion at a club without blinking! Guys like Ashley, Gillett, Hicks etc are worth a few hundred million and to really change their clubs would take every penny they have something they are not prepared to risk.
So now you have to be worth billions and I am not sure who of the new owners is that rich and able to really make change and who is worth a few hundred million and in it for the ego?