I think that the point being made is that we now have 3 popular rendering engines loose on the web: WebKit, Trident, and Gecko. This diversity and competition gives us a much better ecosystem to work within than even the dual culture of IE* / Gecko.
* Trident might not even exist if not for the significant competition (or the name might not be the same were history changed).
* Trident might not even exist if not for the significant competition (or the name might not be the same were history changed).