I think the argument was that the Volt is more complex, but still has a much lower maintenance cost. If Tesla is worried about ongoing service costs eating their bottom line, include the price in the car, don't tack it on as a "service contract" this late in the process.

At $600/year and assuming a 10 year vehicle life, that's an additional $6000 towards the vehicle purchase price. People buying a Model S aren't going to flinch at that (myself included); demanding it as a yearly service fee and creating fear about losing your warranty is disingenuous at best.