I think you will find the economics of the CC will change with the introduction of Matangis and the extension to Waikanae. This is only natural and furthermore was forecast by KR a long time before the extension of the line opened. To say it is because people wanted a subsidy for a commuter rail service is basically a cop-out to serve you own one-eyed view point on that issue.
The CC was paying its way when patronage was lower than it is today. I wouldn't be too quick to believe KR's line that 630 passengers suddenly becomes viable at 668 passengers.
You shouldn't dismiss my theory so quickly either Jon, as what is happening is exactly as I predicted. Time will tell.