For the current applications, an iPhone 5S level of performance - a phone which is 4 years old - is still very usable today. That's also why Android flagship phones aren't really in trouble while still struggling to match the performance of a year-old iPhone 6S, and can't even dream of getting near the iPhone 7's performance. They mostly try to compete with stuff people do notice these days: the camera - where they have a lot more success.
Yes, and remember that Apple intentionally writes OS updates that will run slower on their older devices, thus achieving almost the same thing but slightly less blatantly.
Do you have some strong evidence of this? Amusingly it's actually being tested in court (see the class action referred to in the link below):
http://www.cbronline.com/news/mobility/devices/apple-accused...
This is the reason after using Nexus devices for 5 year, I will buy an iPhone and I will never ever look at Android again. My girlfriend switched from Galaxy note 4 to iPhone last year, and she is amazed how much iPhone experience is better than high-end Android experience.
2 year only update? Give me a fucking break, this total rip off. If I remember correctly even iPhone 5 does get update(and remember iPhone 5 is 5 year old phone, which will get new version of OS, not just security update, this alone is more than lifespan of Nexus or pixel device). Let alone the fact phone processors passed the threshold, phone produced after 2015 are almost as powerful as desktop from ~2005. My point is , if you don't play intensive games or any specific use case, an above ordinary phone would run browser,mail client, chat apps for more than 4 year without any issue. But companies trying to minimize lifespan just because of their own profit.
And my answer to them would be my middle finger.
They are totally screwing up customers.