Earlier quoted context omitted.
Sales levelling off != drying up. Apple has always had problems with their online services, but iOS security is a problem? Compared to what, the dumpster fire over in Android?
Phones are moving towards commodities even apple found this when the X got push back at $1000 per unit.
In other words, people are buying phones less often, because phones for 3-4 years ago are still quite capable of meeting the needs of most users, so people are naturally going to start buying phones less often.
I suspect Apple was very aware of this trend, and the price increase was an effort to increase margins to make up for an expected decrease in unit sales. After all, Samsung also indicated lower guidance on their Smartphone numbers for this year, so Apple is not the only company affected by this trend.
Maybe they missed the mark a bit, and a significant number of potential customers chose not to upgrade this year, but I seriously doubt those customers turned around and bought an Android instead. I suspect they will just get plan to get another year out of their 6S and wait for what comes out this year.