I'm a subscriber of the slower update cycle explanation as well. Everyone I know who owns a tablet is happy with what it does for a longer period of time. Have a look at iPhone refreshes versus iPad refreshes and you'll notice that the iPad follows the iPhone, so it should be no surprise where the iPad falls in the growth trajectory of the company.

Following that same line of examination (looking at refreshes), consider the impact of each refresh. What does a new iPad include?

Thinner and lighter? That's a nice to have, but is it cost-of-upgrade nicer?

Touch ID? How important is Touch ID to users who use the iPad casually. With an iPhone you're frequently operating the device with one hand, so Touch ID simplifies the authentication process. When you're using your device for payments, Touch ID is pretty damned incredible. Neither of these apply to the iPad. I'd love to have Touch ID on my iPad, but it's not worth the cost of an upgrade.

Better camera? I'm an outlier here — almost everyone I know uses their iPad as a camera, except me — but I'm just not sure this alone is enough to push people to upgrade. In the iPhone environment, all of these new features act cumulatively to make an iPhone upgrade worthwhile.

Larger size? Oh, wait. That's iPhone only, and it's probably one of the biggest drivers of iPhone 6/6+ sales. It's irrelevant to the iPad.

Tablets, as a product, involve a slower upgrade cycle because they're actually the more traditional product when compared to a device like the iPhone.

First of all, Gruber is absolutely right that there are still a whole lot of tablets being sold.

That said, sales have plateaued at best and there are probably a lot of contributors:

- Slow upgrade cycle as you suggest. I have a 2nd or 3rd gen iPad and I have absolutely zero reason to upgrade at this point.

- They are probably being squeezed to a certain degree. I find that, even with just an iPhone 6 rather than a Plus, I'm often more inclined to just read on my phone than go grab my tablet.

- I've probably become more quick to grab a Chromebook or some other laptop I have laying around than do anything half-way complicated on my tablet. So there may be some realization that tablets are sometimes more trouble than they're worth even for more complex mostly-consumption tasks.

- I suspect that we may end up with some sort of tablet and laptop reconvergence even though tablets took off in large part because the convergence between the two devices was broken.

Yeah, I believe the slower update cycle too. I have two iPad 1's and an iPad 2, and while I'm definitely due for an upgrade, it doesn't get the same type of price reduction as a phone, so it'll just have to happen in its own time.

As for use - they are constantly getting used for games, movies, books, and web browsing. That is what they are good at. You want a clear use case - its that. My computer stays on the desk most of the time.

>If Apple pumped out over 250 million iPads, a great majority of which is probably still in use, with the usual Android and Windows numbers the whole tablet population must be in the neighborhood of one billion.

How so? Android and Windows tablets never sold as much as iPads and still don't. It might be 50-50 now, but not 3 times as much by any means.

A stylus would be nice. One reason I'm seriously looking at Surface (disclosure: Microsoft employee but all iPads at home).

Chiming in to agree with slower update cycles.

I use my iPad all the time, but primarily for reading and watching movies and TV shows. My three-year-old iPad does these things great and there's simply no reason to upgrade.