Perhaps your usage doesn't challenge the throttling, i.e. you use it for calls, imessage, and apps you haven't updated (thus not as much CPU-demanding) for a few years. I have a Philips stereo on which I can plug/dock older iphones (3-4-5), and for that I got a very old 5, with Spotify. The phone is docked (and charging) on the stereo 24/7/365. So no complaint for that. But if I were to use it for other purposes, it would be super painful to have super slow performance or battery dying on me.