I might get buried here, but tbh, I think it's time for X/8 support to go. It's been what, 6 years? Time to move on.
You will get buried because what you are suggesting is a little out of touch with the masses.
Ask yourself, why if they are still capable devices?
It's easy for somebody in a financially sound position to say these things, but not everyone can afford a new phone year after year. In fact, how often do you change your TV? Back in the day, the iPhone X cost as much as a reasonable TV ($1500).
Would you change your TV after just 6 years and be told, "just move on"?
Better example; What about your laptop? "Just move on!"
Or even your headphones? "Just move on"
We can go even more extreme and suggest your oven needs replacing after 6 years, or maybe the microwave.
I, personally, am fortunate enough to be able to have the latest devices, but not everyone I know is. My mother-in-law uses an iPhone X and that's great because she's a guest in my HomeKit set-up, and it means she's able to disarm our alarm and manage our home like we can through our homes.
She can WhatsApp, iMessage, video call, make real phone calls and send and receive her little videos and pictures, and she's very happy with her phone. Why does she need to change anything?
She doesn't care about cameras, superfast CPU's, efficient cores, high-end GPU's and dynamic islands. She couldn't care less. She just wants a phone that does what her iPhone X does. So long as the OS can run smoothly, supporting it should be in Apple's interest.
This throw-away mentality we all appear to have needs to come to an end.