The first two work just fine in Adobe Acrobat Reader on iOS. The third is garbage, probably because the producer didn't include a ToUnicode map or equivalent.
The format supports a lot that is not commonly implemented by PDF readers (or PDF producers).
And a good format wouldn't require any ToUnicode maps for simple text in the first place
And poorly supporting a lot without common implementations isn't a defence against the charge of high complexity and bad design, but a reinforcement thereof
(also, no, the first document doesn't work on iOS, I select title and two paragraphs, copy, paste, and I get a single line instead of 3, so a different manifestation of the same common fail of PDFs)
The format supports a lot that is not commonly implemented by PDF readers (or PDF producers).