By talking about Viagra you are really picking the low hanging fruit. And yes, I still see plenty of spammy articles on twitter or facebook, and reddit and even here. People have just gotten better at hiding them, so much that they even produce an articles moderately useful to a lot of people.
SEO is sort of the same way in terms of there being a range of options. Some people might use SAPE, Xrummer or Fiverr or such (nude person with a URL streaking at a sporting event), whereas others might use more nuanced strategies where any SEO impact appears incidental.
Design itself can play a big roll in the perception of spam. Designs that look crisp can contain nonsensical content without feeling as spammy as they are.
But another factor here is that Google wants to keep raising the bar over time. Things that are white hat fade to gray then black as they become more popular & widespread. And as Google scrapes-n-displaces a wider array of content types, that forces publishers to go deeper (if they can do so without bankrupting themselves).