I'd say exactly the opposite. PDF makes it easy to create a document that looks exactly the way you want it to, which seems to be all that most web designers want (witness all the sites that force a narrow column on a large screen and won't reflow their text properly on a small screen).
In a way it has. In my experience, there have been multiple times where a "generate PDF" requirement has come up, with the best viable solution being "develop it in HTML using standard tech" followed by "and then convert it to PDF".
[1] https://en.wikipedia.org/wiki/EPUB