Sure, but that's because mobile devices have really small screens. You could create PDFs that were meant to be viewed at that size, but why?

You'd have the same problem trying to read a regular book through a mobile-phone-sized window. That doesn't make books an unsuitable vehicle for document delivery.

It does make it an unsuitable vehicle for delivery of information which people may want to access from a mobile device, however.

Not at all; there is no information that people won't want to access from a mobile device. But again, a mobile device is not necessarily suitable for the job.

Telling your customers to carry a laptop/tablet because you feel linebreaks are just a nice-to-have is quite user-hostile.

PDFs have line breaks.

Mobile devices works perfectly well for accessing this kind of information when developers aren't outright hostile to the users they are meant to serve.

It's not a developers job to tell me whether or not my device is suitable for reading their information because they can't be bothered to make it available as HTML.

> a mobile device is not necessarily suitable for the job.

Certainly not if the publishers took that attitude. And what you consider suitable simply isn't relevant if half the audience is now using a mobile device.

HTML will wrap the text to fit the page. PDFs don't do that.

Adobe's PDF viewer will actually do that. Check it out if you're frustrated by PDFs on mobile.