May be they wont back him if he finishes outside the top 4? We have seen what happens when we finish third or fourth for the last 10 years. Something needs to change to have a possibility of change. I am certain that the board will back him to rectify it as well, but I think it'll at least plant a serious seed of doubt in their mind about renewing his contract.
As for players of caliber joining us.. I think too much is made of this. What players of caliber did Spurs and Leicester have before this season? Or who did Athletico or Dortmund have when they challenged the status quo. A decent captain of the ship is the basic requirement for a good team... good players can be made and can be brought if there is promise. May be we'd need to throw extra cash to get the 'top level' players but we have barely spent anything in the last decade. I am sure we can splash a little, if the need arises.