Yes, education around these scams and their methods could be better, but there is also a reason they target the elderly and vulnerable. Unless something else terrible happens, I assume I will count in one or both of those groups eventually. I feel like when I get there, I would appreciate empathy rather than disdain, if I were ever taken advantage of.

Regardless, you do not actually need to enable developer settings to install APKs from unknown sources (at least, not on my Samsung). When you open an APK from within another app (e.g. Google Drive or WhatsApp), Android "helpfully" forwards you straight to the relevant security settings page, allowing you to immediately toggle the "Install unknown apps" permission for that specific app. It's a streamlined flow, only a couple of taps, no scrolling/searching/reading, therefore likely easy to coach a victim into performing.

So, I expect what the Android team is alluding to in the original post is to enable additional friction like you describe.