We aren't "fanboys" of EverWeb. EverWeb is the closest thing to iWeb, with some additional features that iWeb never had.
Why not just use Google's Sites or Blogger, Wordpress,
Because these are content management systems, not web design tools. You cannot design a web site with these tools without knowing HTML, CSS, Javascript and other code. Plus Wordpress gets hacked all the time.
Weebly, etc.;
These online editors have some benefits such as editing from anywhere but they lack design flexibility (so many look the exact same), require an internet connection, and must be used within a browser. iWeb users, rightfully so, want something similar to iWeb and a desktop application provides a better user experience.
there are lots of free and robust wysiwyg website builders out there
Same reasons as above but also free is not sustainable. A free product is more likely to stop development and then iWeb users will be in the same place they are now. Having to learn a completely new product and redesign their website.
Also, check what you get with the free wysiwyg editors. It is usually a freemium offer so it's not actually free.