It wasn't iteration. They threw away code and started from scratch. Things you should never do [1].

Several months ago Google releases totally new version of Google Maps. Google Maps consistently stays as a poor product since then. I think that even first version of Google maps (introduced in 2005) was better.

[1] http://www.joelonsoftware.com/articles/fog0000000069.html

  When you throw away code and start from scratch,
  you are throwing away all that knowledge.
  All those collected bug fixes.
  Years of programming work.