While Mary Barra probably has more on her plate than arbitrary and specific model support issues, it's still a bad analogy.
You can still get parts for a 1993 Cavalier.
And a '75 Monte Carlo.
Heck, my dad could drive his 1957 Bel Air into the Chevy dealer and get it serviced, like a new battery, if he wanted to.
(Source: employment, family in business, first-hand experience, internet forum comments)
In contrast, I took my wife's otherwise perfectly functional '09 MBP into the local Apple store where they declined to change out a bad battery because it was "vintage" or "antique" or "ancient" or whatever they call it. Absolutely no reason for that to be refused, other than servicing old products keeps customers from buying new ones. I can't believe there is any other reason the new Macs are as sealed up and as unserviceable as they are. The parts are still around and easy to make (and over charge for), the service itself it pretty easy (compared to a new macbook), and Apple store service rates are expensive enough. (See automotive example above.)
I've heard others opine (arguably) and I agree that part of the reason for the PC sales slowdown is because the tech improvements don't improve the user experience, if that experience is limited to email, web surfing and similar light duties. So how else to keep the purchases up? Make throw-away products. Cool for the investors, uncool for the customers - especially the ones like me who got on board with the (waning, if not dead) "think different" mantra.
The emperor's new clothes, indeed.
Your car dealer is not owned by the manufacturer, it's an independent business. Had you taken that MBP to an Apple Authorized Service Provider or other independent repair shop, they would not have refused your business - if they can get the parts (used, refurbished, off-the-shelf, or purchased at close-out from Apple), they'll do the work.
The difference is that the Apple Retail Store is owned by Apple - they have to follow the same Vintage and Obsolete policy as their parts department - "we won't keep or sell parts after 5 years, but we'll keep fixing them" doesn't hold up very well under consumer protection law. Either the company stops supporting a model
across the board, or it continues to support it across the board.
A car battery is not the best analogy, either. In an internal combustion vehicle, the battery is only needed to start the engine. In a portable electronic device, the battery
is the engine.
The size and shape of engine compartments; the size, shapes, and capacities of the engines themselves, are highly variable, like batteries in portable electronic devices. You'd have to do a whole lot of tinkering to put a 1993 Cavalier engine into a '57 Bel Air, and a '57 Bel Air engine wouldn't even begin to fit in a '93 Cavalier's engine compartment.
The dimensions of car batteries have been essentially standard for the past 60 years (or more). They take up a very small percentage of space in the vehicle, so unlike the proportionately huge batteries in portable electronic devices, it's far easier to find the space for a "standard" battery. In terms of the space required, a car battery is more like a single capacitor or chip in an electronic device. Caps and chips
are built to standardized dimensions. Even when the internals of the chip may be custom-designed, the packaging generally is not, in order to take advantage of automated assembly equipment (among other things).
If you were to ask your car dealer, they'd tell you that they do not get parts for older vehicles from the manufacturer, they get them from independent parts suppliers, and sometimes all they can get is rebuilt/refurbished parts. Automakers and electronics manufacturers sell their remaining parts inventories to the independents. The manufacturers are able to remove non-producing assets from their balance sheets (and book a sale), and the parts dealers start a fresh investment cycle. And parts manufacturers (tires, batteries, oil and air filters, hard drives, wiper blades, RAM modules...) simply sell those parts directly to parts suppliers and repair shops.
