Tesla is attracting engineers, because what they are producing seems something useful and world changing, while Apple products while nice, and remain to be great products. But Musk's empire Tesla, Space X, and SolarCity. are bringing grander changes to the world, Something that perhaps history will look back with fondness, on our generation and say we accomplished something. While the generation preceding this Apple was credited for the personal computer for the masses, the iPhone and iPads while wonderful technology are at best would be footnotes in history.
No, not really. They brought PDA technology to the masses in a way that Palm et al failed to do repeatedly. Unfortunately, now that Apple has done that, there's really no more room for significant innovation in that space. The products exist, and the market is mature; you can make small, incremental improvements, but otherwise, the only thing left to do is to drive the price down to the point where everyone can afford one, and that's not likely to increase profits by much.
Apple's biggest problem has nothing to do with coming up with the next iDevice, and everything to do with the flawed assumption that this "killer new device" should be an iDevice in the first place. Apple has gotten into a rut where every new product since the QuickTake (or, arguably, the iPod) has basically been a new variation on a computer. I mean, an iPad is basically a laptop without the keyboard. An iPhone is basically a smaller iPad. So when you look at it from a high enough altitude, Apple hasn't really come up with any new hardware products in two decades. Even the Apple TV is basically just a little general-purpose computer. Apple is basically a one-trick pony at this point, and they've had an amazing run at it, but like all companies that are too focused on a narrow area of technology, there's only so far that they can go down that path before the market becomes saturated. And eventually, a disruptive player will enter the market and start eroding its market share, and then the company will become another Microsoft, and that new disruptive player will become the next Apple.
There's only one way for Apple to avoid that fate, and that is to expand its focus by building something that isn't just a glorified computer in a different form factor. Apple could do this either by disrupting an existing, struggling market or by starting a new market for a new class of products. That second one is hard, but the first one is easy. And Apple's existing technology could be used synergistically to dramatically improve the products in those markets.
If Apple is willing to take on a niche market, the DSLR market has a lot of room for improvement. It won't ever be a huge market, but it is likely to remain a solid pro market for the foreseeable future, and would be easily disrupted by a company with the hardware engineering resources that Apple could bring to the table. And if they bought Canon (market cap 30.59B), they'd get a great collection of well-built lenses, good lens engineers, and a respected brand name that they could build upon. Now imagine a DSLR that integrates well with iOS, runs a better OS under the hood, and has a more capable CPU to allow for amazing features that just aren't possible right now.
Apple could also buy iRobot and add iBeacon support to Roomba's existing Wi-Fi triangulation to produce an absolutely jaw-droppingly accurate automated vacuum system. It could automatically avoid areas that you mark as sensitive, use visual sensors to avoid sucking up your Lightning cables, and so on. It could tell the difference between the cat and a piece of furniture, and slowly creep up on the cat until it gets the message and moves. And they could bring the price down to something that normal people can afford, by taking advantage of the Apple hardware teams' skill at reducing manufacturing costs and increasing yields.
Apple could buy Tesla, use their battery tech to improve Apple's laptops and cell phones, and use Apple's tech to improve the in-car experience. It could then make Apple stores be "showrooms" to get around all those pesky state laws requiring a physical presence for sales within those states. Synergy.
Apple could buy Disney/ABC/ESPN and make live streams available by subscription on Apple TV for people who have cut the cord. This would, of course, immediately bring all the other networks back to the table in a state of panic, and they would finally succeed in turning cable companies into dumb pipes. It could then spin it back off to avoid various conflicts of interest that would likely hurt the quality of Apple's hardware and software products in the long run (see also Sony).
Apple could put money into solar and biotech research, along with any number of other fields that could use a shot in the arm.
There are so many amazing things Apple could do with its huge cash horde that could revolutionize the world as we know it, while simultaneously being great business moves that would open up new markets and new revenue streams. Not all of them are insanely exciting, but all of them are potentially quite profitable. Apple just needs to have the vision to take that next step towards building products that are more than just a computer in a different form factor.