This won't be the case. Here's why.
As with any new iPhone there will be a massive uptick in sales in the quarter following its release. I have no doubt that we will see a record number of iPhone sales reported once the 6 has completed its (their?) first sales quarter. Whilst some of this will be related to upgrades and some new users coming into the iPhone fold, the major factor in each new release has been the increased number of iPhones available and the greater number of markets at launch.
In truth, the growth over the lifetime of the iPhone 6 will be an improvement over the 5S/C, but incremental rather than by magnitudes. The rate of iPhone growth has been slowing since 2010. That's to be expected as a market matures. In order to match the 20% growth of last year Apple needs to sell 51 million iPhones this quarter - which would be a record in any quarter, never mind the generally average Q4 reporting period.
|iPhone Sales Figures by Apple FY|
In the premium smartphone market Apple's market share is likely in the region of 75-95%. There aren't huge numbers of competing devices here that have anything like the sales to challenge Apple's. If you take the Galaxy S5 as premium then it probably all but consumes the market share left after Apple has had it's take.
The thing with premium phones is that they are expensive (outside of the US anyway, where subsidies flatten the price curve and the iPhone does disproportionally well) and as a result they aren't available to the greater part of the potential customer base. The iPhone owns the premium market and it's share of that market moves between very small limits.
At the current level of market maturity everyone who can afford a iPhone is buying one. Those who can't have to make do with an alternative cheaper device or buy second-hand. The potential increase in iPhone sales is only ever the 5-25% of the market it leaves on the table.
However because Apple maintains the iPhone pricing structure with each new release, the affects of inflation and salary growth mean that in real terms buying an iPhone gets less expensive with each new release. The size of the market is growing. In populous developing countries - China and India in particular - the increase in the percentage of people who can afford to buy an iPhone need only be tiny to create a significant number of new customers.
For Apple overall market share is not a concern. A 20% year on year increase in iPhone sales may sound weak - but only in the context of the remarkable period of growth experienced as the smartphone went from niche to mainstream.
|iPhone year on year sales growth|