The iPhone SE (2016, A9/2GB) is both newer and faster than the iPhone 6 (2014, A8/1GB).Let me tell you a secret my family learned, Apple stinks. My dad got a 6 to replace his SE (which became my phone) and he hated his 6. The 6 never worked and after a while, it just broke. My little brother's iPod just broke out of nowhere (he didn't do anything wrong with it) and my mom refuses to repair it. What do these devices have in common? They are all newer devices! My dad also said, "the SE is Apples's last good phone". On the topic of my dad, he read a bunch of articles saying that Apple's newer devices just break after a year. Also, I had an iPad mini 2 and loved it (I broke it and I don't have the money to repair it), so for my birthday I got the original iPad mini, and I hate it. The OG mini is super laggy, never updates, and it has no storage.
I really wanted to get an animation app but it requires iOS 10. Guess what? My iPad mini 2 updated a lot and I could've gotten that animation app on it! If I were to recommend Apple devices, buy the older ones because they came before Apple realized that they could make more money by making the newer devices to break. Another thing is that Apple's products are super overpriced. So don't be fooled by the "newer device means better", because that is just a false reality that humans want to believe.
Of course the OG mini is slower than your mini 2. It's got A5 chipset and is two processor generations behind the A7-based mini 2, not to mention only having 512MB vs 1GB RAM.
Maybe you want to use other examples for your "older is better" argument since your examples clearly show the older devices performing worse.
I still have the OG iPhone, iPhone 4, 4S, 5c, 5s, iPod touch 4th gen, and iPad 4 and Air in my possession. They're all super slow and laggy even compared to A9-based devices (released circa 2015-17). Old models also received far fewer firmware updates and they experienced greater performance degradation with each update than iOS devices with A8X/2GB or A9/2GB and newer do (barring the iPhone battery snafu). I'm still using the 2016 iPhone 7 (A10/2GB) and compared to my brother's 2018 iPhone XR (A12/3GB), I don't notice a difference in performance.