If I were Tim, the next ten years would primarily be:

* Car; not happening.

* Connected home; this is a crowded space, but it also represents a class of products that people are willing to invest in, then keep for years; Apple is great at this. The most obvious product would be a thermostat, then extending into cameras, sensors, and door locks (imagine a camera which uses the FaceID laser array tech to build a 3d representation of some interior space, for more powerful object detection). The reason why I think this is an "obvious" next play is because it very naturally leads to a new billable service; right now, iCloud storage plans include some amount of homekit secure video storage, but its easy to imagine a new "Apple Home+" plan which includes that, plus other stuff like 24/7 on-call security and advanced object alerting.

* AR; positioned primarily as a value addition to the iPhone like Airpods. I think this will be less popular among older adults, more among younger people. I'm only slightly interested, and I'm late-20s; people younger than me will be far more interested, and that does matter. For me: if they look enough like normal glasses, have some kind of health angle to them (idk, EDA sensor by the ear? read my brain waves?), and "built-in Airpods" via bone conduction tech, I'll likely pick them up; I already wear glasses, why not make them smart.

* Watch; continue to grow sales by investing in health-focused monitoring and services. Noninvasive blood glucose would be the biggest possible thing they could do here, and would massively drive sales, even if it were isolated to a (even) more expensive "Apple Watch Pro"; anything below $1000 would be an instant buy for many diabetics, of which there are... so fucking many.

* General health; continuing to invest in preemptive detection technology. This class of tech, mostly algorithms and new sensors, is the biggest, safest, craziest moat Apple will ever build for itself. Its definitely a bit of a FUD marketing angle ("Apple Watch can detect if you may be developing parkinsons", ok i never had that before but now I need it). Very curious to see whether Apple starts locking more advanced detection/trends algorithms behind a subscription service (Health+, or another), similar to what Fitbit does; could see it go either way.

* Mac; there is so much potential in converting Windows users, between the value statement of M1 and the lukewarm response to Windows 11 (its still ~10/90 split!). Gaming needs to be the short-term focus here. It just Makes Sense. A proton-like compatibility layer seems easily within the capabilities of Apple's engineering team. Additionally, Apple should work with just a couple major developers to bring support to a few keystone titles. Combined with a large marketing push (its what Apple does best) and the continued graphics card shortage (no end in sight yet), this would be a relatively small investment to grow Mac marketshare by single or even double digit percentages. The value statement for developers is way too good, they just need a push; release on Mac, gain near-zero-configuration access to iOS, iPadOS, and Apple TV devices if it makes sense for your game.

* Fintech: An Apple checking account is inevitable I think (imagine Apple Cash, with a debit card and direct deposit, that's all it takes, even a competitive interest rate isn't necessary anymore). This will be an obscene source of liquidity for the company, as an entire generation of affluent young customers eschew traditional antiquated banking services. I don't believe we'll see them touch cryptocurrency in the next ten years; as another said in this thread, Apple is the Disney of computing. Crypto is still too "weird" for them, even looking beyond the environmental implications.

* VR; I'm much less certain Apple will ever get into VR, but I think the argument is stronger than many people admit. The technology is here already, unlike AR which still feels like people don't know what it is. They have an extremely powerful SoC which can fit inside a Quest-like AIO (this is the current challenge Valve is facing competing with Oculus, but they'll get there). Most critically: the only people who believe "VR is for gaming" don't have a VR headset; VR's strongest use-case, bar none, is exercise-gaming (this is why Oculus recently acquired Supernatural and Beat Games). That's why I think it makes sense for Apple; its a nexus of two domains they're very strong in today, and have expressed desire for growth.

In short, I don't believe there will be a "next killer product" for Apple, or any company. The low hanging fruit has been picked, and the next phase of computing (more accurately, the one we're in right now) is the "last 10% is 90% of the effort" work in making everything we already have do more, better.