Jim, the concept is right, it's just that concrete tends to go bad in sections rather than in small pieces, even when it's poured in small bits. There would probably be 6 or 7 slabs replaced in one area and then a fair distance between that and the next area that got repaired. If there were aw many slabs needing replacement as what you show, it would be cheaper to tear it up and replace it since the labor costs to keep replacing bad sections will eventually get higher than replacing the whole thing.