I'm aware such people exist, I just don't confuse that fact with a belief that a majority of readers don't have problems with the experience of e.g. trying to read a PDF on a phone or anything else that isn't at least A4-/letter-sized (heck, PDFs have fewer people read them than would otherwise even when the person doing the reading is using a desktop or laptop)—precisely because PDFs preserve the presentation for print.
> How do you annotate blog posts, and in way that is preserved for decades.
Is that a statement or a question? In any case, it's hard to begin to conceptualize what sort of misunderstandings about the relevant media could lead to either. Blog posts (published originally as HTML, that is) are not inherently less susceptible to being saved than an academic article published as PDF. I did, however, already mention Zotero (and SingleFile).
> I almost suspect we are somehow talking different things, because even the most non-technical users know that about PDFs. But also it reads like you are finding a way to disagree with everything.
Am I? I'm pretty sure that I understand what you're saying, at least, and that we're talking about the same things. I don't know what you expect, though, when the fundamental premises are in dispute. There's no way to just "yes-and" through disagreements like that.