No one wants to carry a 10 tons rol of steel in a sports car. The majority of people getting a PDF on their phone though, do want to be able to read the information in it easily and they can't.
I don't know much about steel coils, and I'm hoping that something that fits in your back seat isn't as dangerous as those featured in YouTube videos, but the idea that the primary concern is just strapping the thing down is kinda funny
Shouldn't "portable" in the context of a document format mean "comfortably viewable on most systems" rather than "yeah you can view it but it's gonna suck and you'll get eye strain"?
I believe this is called "responsive design", a useful but differentiated concept.
It's pretty cool how PDFs don't typically load resources from an external website or CDN. They are self-contained, and thus demonstrably portable.
Gross analogy: Have you ever been to a multi-day music festival? A port-o-potty in the dark is disgusting, but still somewhat useable compared the alternative of going to the bathroom in public. PDF artifacts are in the same ballpark.
Also, I think I'd personally dislike a "portable document format" that doesn't look identical on all systems. By making it visually identical everywhere, you of course sacrifice comfort on smaller screens by nature. But to me that's an acceptable tradeoff for knowing I'm looking at the document, as it was intended to be displayed. I don't think of PDFs the way I think of websites. My physical papers don't reflow text.