I haven't access to the Fitch article, and I'm no specialist of the automotive market at large. I know even much less about oil. However, here are a couple of guesses about how things are likely to go wrong for car makers.

In a vertical market like cars, you've got many actors, from iron ore mining to the "going from A to B reliably" service, going through part makers (who actually make most of the car), car maker (brands), repairmen, dealers, etc. Very often in those markets, one actor controls a key level, protected by entry costs, secrets, regulations, exclusive customer relationship, whatever. By leveraging this stronghold, this actor extracts most of the margins, leaving just enough to other levels to let them survive. You want all other levels in your vertical market to be commoditised: Microsoft wants PC hardware commoditised, Über wants driving to be commoditised (through underpaid drivers first, unpaid robots ASAP), etc.

It seems that for cars, mastering the engine is the way to control the whole vertical market. Moreover, ever-more-stringent emission + fuel efficiency regulations keep it hard to make engines, despite technical progress. Electrical cars change that, because it's (comparatively) very easy to make an electrical engine.

Another asset held by carmaker is the brand and consumer relationship, and this one's probably doomed as well. Cars stay parked for 95%+ of their lives, the only reason you buy one (and it's your most expensive possession after your house) is because you want it to be reliably available whenever you want. Once cars drive themselves, it stops making economical sense to own one: for a fraction of the price, you'll rather subscribe to a fleet of autonomous cars which reliably deliver one on your front door 10 minutes after you summoned it with your smartphone. That not only means fewer cars driving a higher percentage of time: it makes obsolete the car-makers' genuine expertise in making individuals want to buy their models. I'd bet that selling hundreds of thousands of units to Kalanick is significantly tougher than making some hillbilly lust for a Canyonero.

It looks like mastering level-4 autonomy will be the new way to lock that vertical market, and current car-makers don't look better positioned than the Silicon Valley to secure that stronghold. Cue the famous last words by the then Palm CEO, saying about the iPhone “PC guys are not going to just figure this out. They’re not going to just walk in”. Yes, in radical changes, it typically is an incumbent who figures it out.