One reason is for continued software support after Apple drops macOS compatibility for your machine. Intel Macs could be patched to run newer, unsupported OS versions (essentially hackintoshing your real Mac) but from my understanding that's basically impossible for Apple Silicon Macs.
I think there's also now less of a gap in features between the two. My Galaxy S7, when new, had tons of features I could flex on iPhone users with (water resistance, always-on display, 1440p OLED screen, wireless charging, etc.) but now iPhone Pro models have basically caught up, with iPhone "Normal" models only losing out on things that the average consumer doesn't care about. With this happening at the same time as the "feature drain" that you've described, it means there's fewer and fewer reasons to buy an Android.
Purism is insinuating that the primary reason why Apple throttled phones was to force you onto a new one, which is false. I think most people would rather have a phone that runs slow than a phone that randomly shuts off (increasing the lifespan compared to doing nothing and making people think their phone was broken.) Where Apple went wrong was not telling anyone they were throttling their devices, and not letting you force them to run at full power (which they changed later after the media backlash.)
People who use third-party apps are the most likely to be invested in the platform but they don't matter at all to reddit, the company. I would assume that they are also the most likely to use old.reddit, the most likely to use adblockers on desktop, etc. Reddit would rather replace them with people that will just use the default mobile/desktop experiences because they're the easiest to set up. That is the gain. NPCs are easier to develop apps for because they don't care if the apps are actually good.
The ReMarkable is so tempting but so expensive. It's just hard to stomach spending $500 at a minumum for the tablet + folio + stylus when I could have an iPad (a gimped base model one, but still) for the same price
My first computer was a Raspberry Pi v1 that I got when I was 9 (now 19). Definitely not the case for me. I became proficient in using Linux very quickly.
From personal experience this is mostly due to iMessage chats. Imagine for example that all of your friends have iPhones except one or two. From your perspective, they're the reason you can't have an iMessage chat with all the fancy features. Sure, you could use another messaging app, but why couldn't they just buy the phone that always works?
This perspective doesn't make sense to me, but it's how a majority of people think.
Do No Harm, which the author's a part of, is an alt-right group intending to "fight against identity politics" in healthcare, with one of the sections on their website being "Protecting Minors from Gender Ideology." That sure explains a lot about the contents of the article...