Google seems like a particularly bad acquirer for this as well, since they have no relevant expertise, market position, interests, etc. They don't manufacture anything, they don't sell physical products, they don't even really sell nonphysical products other than ads.
Look at what happened with Motorola Mobility, for example. Google paid a ton of money for it, basically dicked around for a couple of years with it doing nothing of note, then vomited it back up again. Thankfully Motorola Mobility was not terribly remarkable to begin with so it wasn't a big loss.
Google fairly overtly bought it for the patent portfolio and had the plan to resell most of the rest from day one. The thing Google was buying was the patents, the rest of Motorola Mobility was packaging.
Contrast with Android, YouTube, or anything else where Google wasn't buying patents or doing an acquihire, but actually buying a company for a product.
(Google probably looks worse in some respect for products because it has the kind of reserves that let it spend money for big acquisitions when all it wants is an acquihire or some resource like Motorola's patent portfolio and doesn't have any plan or concern for the main product, but I think that's an indication that it is bad when it actually is buying for product.)
I don't know how big a deal the self-driving cars thing is at Google, but a giant car/battery company sounds pretty complementary to that.
Motorola went from phones I would advise everyone to avoid to phones I actually advised family members to purchase in that time. They're basically the low cost nexus at this point.
Shit, a self-driving Tesla, now that is a car worth saving every penny for...
Don't get me wrong, autopilot is super cool and really useful. The autopilot features that are currently enabled in my Model S are wonderful, and I can't wait until they're all there. But they won't be even close to full self-driving. All it will do is maintain speed intelligently based on the car in front of you, automatically stay in your lane, and switch lanes on command. It won't switch lanes on its own, it won't stop at stoplights, it won't make turns for you, or do any of the hundred other really difficult (for computers) things that are part of everyday driving.
Relevant: http://www.asymco.com/2015/02/23/the-entrants-guide-to-the-a...
I'm pretty sure the opposite has also been seen [0]; what's the basis for concluding a Google acquisition would have put Tesla closer to the "never heard from again" side?
[0] Google's acquisition of Android, for instance.