It is a certainty that Keegan would not have agreed to return unless Mike Ashley had committed to sanctioning a mammoth spending spree. The downside, which Keegan will soon discover, is the law of diminishing returns in a league that is now the richest in the world. The type of multi-million-pound investment that bankrolled the first Newcastle revival under Keegan is now two-a-penny. Buying success just isn't as easy as it used to be. The Premiership's paradox is that the more money there is, the more the art of management gains in value.