Re: Maybe iPads just have a longer life?
I agree with much of what you say... I have the same generation iPad that you do and it serves it's purpose brilliantly as a casual sofa surfing device, a Netflix viewer for my girlfriend when she is getting ready in the morning and a very occasional gaming device. A few games stutter slightly, but it's the smallest of niggles, and I do quite frequently momentarily wish it had Touch ID when I absent mindedly leave my finger on the home button waiting for it to unlock like my iPhone. I hand off to my mid-2010 MacBook Pro when I need a proper home computer which is maybe a couple of times a week, a device which increasingly shows it's age but continues to serve it's purpose. Both are devices I fully expect to upgrade, but both only on a 5/6 yearly basis unless technical failure happens first or unexpected incredible technical innovation occurs.
My iPhone though, perhaps due to it being used much more than either of these devices and the limited life of lithium ion batteries being more obvious on a device that is outside the home far more frequently, has always been one a 1/2 yearly upgrade cycle and I imagine this will continue. I don't know how typical a customer I am, but I would hazard a guess there are many of me about.