Because they'd be back to having a rough running odd fire engine that wouldn't sell as well.Sounds WAYYYYYY too complicated for absolutely no reason whatsoever lol. Just center everything and be done with it lol. It actually sounds like more work to go out of your way to ensure it wasn't on center lol.
It was less work to flat spot the rods and use the same block and heads. It was defiantly a compromise decision that they got away with.