Greed is one of the seven deadly sins in life and Jonathan Rowson’s fine book extends the notion of a sin to the chess board. Gordon Gekko said that greed in good in all its forms, but the Wall Street Michael Douglas character must not have played much chess because the following chess position is an example of Black neglecting his development just so he could say “See I have an extra pawn!”
The chess position you see occurred 6 moves into a Catalan Opening after Black played 4. … dxc4 and then decided to hang on to his extra pawn come hell or high water! White need not formulate a plan based on “winning back his lost pawn”. If he develops normally, then Black’s neglect of opening principles will eventually be revealed. Rowson’s The Seven Deadly Chess Sins does a beautiful job of refuting distorted perceptions of material value in a chess game.
More concretely, the time Black has spent protecting his ill gotten gains, the protected pawn at c4 , has left his King in the center and his King side unmoved! White must not direct his actions towards getting his pawn back, but take over in the center which will hinder Black’s piece development. Consistent with this strategy would be 7. Nc3 or e4.
So why does ICC’s Stockfish and Houdini prefer b3? The move b3 observes that Black has used 4 precious tempi placing pawns at a6, c6, b5 and c4. Perhaps Black is fantasizing in Silmanian fashion of sinking a Knight into the d3 outpost after the e pawn moves. White’s move is an attempt to refute Black’s greedy strategy of ” winning a pawn” by not allowing a consolidation of the Second Player’s Queenside pawn mass.