It did and I think you will find that iWeb 09 still works with Yosemite and El Capitan, although some people have reported encountering some problems with iWeb 09 and El Capitan. The problem is that you are still using iWeb 08 and I think you would find that if you had iWeb 09, you would not be encountering these problems now. As it is, you may find it hard to get hold of unsupported software now.
The whole reason that Apple ditched iWeb, was because it got rid of firstly dot Mac and then MobileMe - MobileMe was Apples own hosting platform and they decided that iCloud was the way to move forward for storage, but not web hosting, so there was no longer any need to iWeb, which is why they stopped developing it and stopped support for it.
Apple is better at developing the hardware and I think they probably decided to leave the software to other companies that concentrate on it, such as Rage Software that produce EverWeb.
Either you need to upgrade to iWeb 09 - Amazon or Ebay and look for either the iLife 09 or iLife 11 boxed set, both of which contain iWeb 09/3. However, upgrading to unsupported software is not a good idea, so I would suggest that you take a look at the alternatives out there and find something that suits.
There is RapidWeaver, Sandbox, EverWeb, Flux 6, Freeway Pro/Express, Adobe Muse (not cheap) and you'll need to pay on an annual basis for this. You can then consider the online web builders such as Wordpress.com, Wix.com, Weebly.com, Moonfruit.com and others. However, remember with these you need to publish the sites to the servers of WordPress and Wix etc, but you can add your own domain name if you wish.
If you decided to go forward and use the Content Management System's (CMS), then these are free to download - take a look at Drupal, WordPress.org and Joomla.
There are many alternatives out there that you can use at affordable prices.