Saturated? Not really. Evolving? Yes.
As the market ages, Unit Growth vs. Percentage Growth changes and the double digit percentage cannot be sustained. As "WOW" features become less common, folks start looking deeper at overall cost. It becomes harder and harder to mentally justify paying significantly more for one setup when another similar setup can be had for much less. Market evolution. Predominately why Apple needs another "Big Thing". There will always be the "Gotta Have iPhone/Galaxy/..." folks who view it as more than. For the rest, especially emerging, aged, or lower economic markets. You only have to look at Huwaei for an example.
Agree completely with this.
iPhone growth was largely by chasing new markets..
It started off a high tech early adopter product.
Then they grew to a product for the entire family. Wasn't just a tech savvy mom or dad, it was time to get an iPhone for the kids and grandma.
Then they expanded to every possible corner of the globe with China being the last untapped market to drive huge sales numbers.
Their final card was increasing the screen size to match the competition.
All the 'easy oil' of sales growth is gone. Upgrades will provide a steady source of revenue, but there are no big markets to conquer and seemingly no new innovation to drive the product. The built in obsolescence is probably their greatest feature. If phones had the same lifespan as a tablet, it would be a lot uglier.