Financially Apple has been growing by adding new territories and carriers (NTT Docomo and China Mobile after the 2012 crash, in which there wasn't a sales decline but a margins decline and a growth pace decline). Now it's reaching saturation when talking about territories and carriers, so it has to:
-Wait until middle class grows in China and others (too slow)
-Convince their installed used base to upgrade
-Increase market share in those territories.
They're trying to convince old customers by new designs and specs bumps -too slowly-, they're trying to increase market share by increasing the screen sizes offering -already done- and lowering prices.
Now, if this makes no effect, and the results which will be released this quarter are the start of a new trend, in a year and a half or two, you'll see Tim Cook's head being served to shareholders. Then, Rome will be burning big.
Quite all the institutional shareholders have been selling AAPL since last summer. iCahn and Einhorn have been selling AAPL since late 2015, and I'm not talking about making cash for covering energy positions or a market correcting, I'm talking about the own problems Apple is facing. If the trend doesn't reverse, this will be a very serious problem and another 90s style era. If the iPhone growth is really dead, and there is no substitute, this will get ugly.