With Apple reporting lower-than-expected iPad sales for the second quarter in a row, it’s likely that Tim Cook will be once again be called on to reassure investors that the decline in year-on-year sales won’t continue indefinitely.

Cook has been very bullish on the iPad, despite the numbers, pointing especially to growing sales in the education sector and the opportunity for tablet growth in enterprise.

I think he’s right, especially with the IBM partnership. I mentioned in my opinion piece then that increasing penetration in enterprise could also help drive consumer migration from Android, as it gives people exposure to iOS devices. But the impact this has could well be offset by the iPhone 6 … 

The penetration in business is low, it’s only 20 percent. If you looked at the penetration of notebooks in business it would be over 60 percent. We think there is a substantial upside in business.”

iPhones are remarkably capable devices, and I’m always amazed how much people manage to get done on them. I even met someone who wrote parts of a novel on his iPhone while travelling on the London tube (metro).

But many of us find an iPhone screen a little cramped for prolonged use, and for most things on the move I’m more likely to reach into my bag for my iPad than into my pocket for my iPhone. That desire to have the same convenient access to mobile apps but with a bit more breathing room is the reason the iPad exists.

Personally, I’m a fan of big screens. My main Mac is still a MBP 17, and I have the iPad Air rather than the mini. But plenty of people seem to find the iPad mini a good compromise, offering enough room to work in a device which is still extremely portable. The question that has to be asked is: if those people are happy with a 7-inch screen, might they be just as happy with a 5.5-inch one?

Apple has never been afraid to cannibalise its own products. Cook is on record as saying they Apple accepts that iPads cannibalise MacBook Air sales, but “if Apple doesn’t do it, someone else will.” But cannibalisation of iPad sales by the iPhone 6 could be a rather more worrying phenomenon …

If an iPhone owner opts to buy an iPad instead of a MacBook Air, Apple makes less money but still sells a second device. But if someone who currently owns both an iPhone and an iPad mini decides that, next time around, they’ll just buy a 5.5-inch iPhone as an all-in-one device, that’s a completely lost sale.

I do think this is a significant risk. I know a number of people who opted for an Android handset when the first 5-inch models came along specifically because they wanted to carry one device rather than two, and for them a five-inch screen was big enough to perform the duties of both a phone and a tablet.

For most of us, a platform switch would be way too high a price to pay for a bigger screen, but once people can get that larger screen in an iPhone, it’s likely that a significant number will find the single device route an appealing one.

If we’re considering iOS sales as a whole, I suspect the iPhone 6 will have a positive effect. There are plenty of people who’ve been waiting impatiently for a larger-screen iPhone, and I suspect we’ll see significant migration from Android. Both frustrated iPhone users who left the platform to get a bigger phone, and Android users who’ve been eyeing the Apple ecosystem jealously but who weren’t willing to downsize.

But what is good news for the iPhone could, if enough people opt for the ‘one device does it all’ approach, prove a significant threat to sales of the iPad mini in particular.

If you currently have both an iPhone and an iPad (especially an iPad mini), what are your plans once larger-screened iPhones are available? Keep buying both, or will a 5.7-inch iPhone be good enough to do it all? Take our poll and let us know your thoughts in the comments.

Main image: martinhajek.com