I'd agree with Yuki on this.
I'm currently updating my site and trying to fix it up and add new content. If I was to put in the time the site really needs it would be almost the same as 2 months of constant working hours. To just figure out how to move and re-setup the messageboard on WG.com when I changed service providers took about 4 working days, that is outside actual work in fixing it up and getting it updated to a secure standard. That's just to get it back to a working standard. This weekend I'd like to make it a little more Guyver like and put back in some logos etc to make it no longer just a plain messageboard.
That's just for a place for fans to chat with each other, getting new content together and presenting it in a nice way also takes a lot of effort.
Simple fact of matter for me and I doubt it's much different for Yuki is we do this as it is fun for us and we care for our respective sites. While the idea of "oh we could sell this for loads of money" the valuation would never reflect it's true value to us, which is priceless.