i agree, there are a lot of limiting factors. in addition to the ones you pointed out, the franking commission also places a lot of rules on wha websites can and can't do. in order to get a winning website, you are basically required to break the law. That's what we had to do in order to get our golden mouse this year. 

another limiting factor is the restrictions on web technology because of budget and availability. there are only a few companies who have overcome the stringent security restrictions required for congressional websites (as well as other sorts of red tape). even if a staff member had the technical knowledge to put up a drupal site, for instance, we don't have a server available to install it on.