Firstly, the cost to certify a car for EPA is enormous. It isn't a few thou. So given the modern take rate on sedans (even on a v8 sports sedan) they will indeed cover the cost by dividing the cost amongst the projected sales. So if it cost $100,000 to certify, inventory, update dealer doco, parts inventory/wharehousing etc etc etc and they sell 500 manuals then bingo.
As far as stocks on the ground, a boat might have recently landed. Another one might not come for weeks. So dealers might have just got an allocation that will have to last them months - and America is blanketted in snow, hardly good weather for selling anything. All car sales are down. It's summer here and they're knocking out lots of cars. This is not an Impala or Corvette or CTS where there is a factory on the same continent knocking out cars. These cars come from a long way away.
Don't trust the dealer locater. Dealers don't remove inventory to get you on their lots or just because they're slack. Same thing happened with GTOs and G8s - people went looking for cars sold weeks before. In the last month of GTO sales the website was showing 2,000 for sale. A Pontiac staffer posting to the GTO board said there was less than 200 new, unsold cars which did not include dealer demos and they were all 17" wheel all-weather tyre autos - the undesirable ones.
As far as options, the 2015 is likely to be the last model built. Intel about Holden's operations such as they are suggest they are going to build enough cars in 2015 to see out demand for PPV, SS and Holden VF demand until the end of 2016 and close the factory - Cruze will be gone by then and the factory can build 100K plus a year and is currently only running at 60-70K. And in case anyone missed Reuss' comments, there is no 'next gen' SS. Holden engineering is winding down, everthing that is likely to be offered is already in the can. Holden had DI protos back in 2007 - not going to happen.
GM is leaving the field. The last company who could give GM a niche hi performance RWD sedan at less than Cadillac prices is being closed. GM is just going to sell you American Toyotas.
And while the G8 is a worthy car, it's interior and amenities were borderline acceptable in 2009. The VF/SS is right up to the minute in features and fittings - it is it is simply far more capable in virtually any circumstance. Not only does it have wider rear treads, but superior suspension and driveline tech, and steering and handling. Comfort, drive, features. Even the auto is much better sorted. The manual is not the same box as a 1993 T56.
If you had a clean G8 GXP it might be a tough call as that is not a terrible car. You could persuasively make the same argument for a Sigma CTS, pre-2012 Charger or 300, even Corvette. The new car, is better though in virtually every way.