This means that either 10nm manufacturing wasn't ready at the time when Apple started mass production of the iPhone 7 and iPhone 7 Plus phones or that it was too risky for Apple to use it on its first quad core chip for iPhone 7s. Both reasons could have affected Apple's decision to make one more 16nm SoC and give it exclusively to TSMC. Apple had to start working on A10 in 2014, if not earlier, as this is roughly how much time you need to finish a very complex SoC.
Since TSMC has already said that it plans to start the 10nm production in late 2016, this was too late for the Apple upgrade cycle. Apple didn’t use dual sourcing with Samsung and TSMC for the iPhone 7 as the SoC was exclusively manufactured by TSMC. One might say that TSMC has more experience with these complex chips.
Snapdragon 830 will launch later this year and ship to customers in late 2016 or the first days of Q1 2017. We expect to see Snapdragon 830 powered phones at the Mobile World Congress in late February 2017 and some brave manufactures might even launch at CES 2017 (January 5. 2017) or shortly after. Fudzilla has been certain that the Snapdragon 830 is a 10nm SoC since April 2016.
This will be the first time in years that Qualcomm launches a chip that is using a more advanced manuacturing process than Apple. It might give a company a big advantage. Fudzilla also expects that the 2017 Exynos (Exynos 8895 could be its name) will use the 10nm FinFET process and it seems that even MediaTek will launch its 10nm phone SoCs before Apple.
It is rather easy to expect that the company's next iPhone units will have an A11 SoC with 10nm FinFET transistors, but these two phones will launch in September 2017. This doesn't necessarily mean that iPhone lovers will jump and change their phones for Android ones, but it will definitely put the Android alliance in a bit better position.
Phones such as Samsung Galaxy S8 with 10nm SoC will potentially have a big advantage to iPhone 7 since they can pack a rather larger GPU and clock both CPU and GPU potentially higher compared to a 14nm SoCs. Only time will tell.