> Last month, Apple released an update for the iPhone 8 and iPhone X [1]. The iPhone 8 was released September 2017. I seriously doubt 9-year old Android phones, even flagship models, are still getting software updates.

How usable is an 8-year-old iPhone as a primary phone though? I agree that having 8 years of support is a good thing, but at that point the hardware is so degraded that it's not suitable for its original purpose anymore. At that point I'd rather have android just so I can root it and install Linux. Then again, with improvements to phones slowing down in recent years, this is becoming increasingly untrue.

Samsung's flagship Galaxy series get software support for 7 years. A, M, F mid-range and low end models get 6 years of software support. The worst case today for the most popular mid to low spec phones is twice the "a few years" you claim, which suggests you're out of touch with the changes in the industry over the last few years.