The problems are, and I can speak from experience now having been involved with a company responsible for running the web site (in fact, on more than one occasion):
1. The Broncos refuse to pay decent money to the design company. Usually barely enough to cover the graphic design labour to design the template. They take the lowest bidder, regardless of whether they're any good or not, and if someone is good and they want them, they'll make them match the lowest bid to get the job.
2. The Broncos expect the web company to come up with all these whizbang ideas for the site, and to maintain content on the site other than basic news. This would be OK except for point 1.
3. The Broncos themselves put very VERY little effort into the web site itself. Only the PR guy is involved, in posting news items, match reports etc.
4. Web companies propose all sorts of exciting things for the site to bring in lots of visitors etc etc, and the Broncos salivate over it. But when said-web company proposes the cost, the Broncos go "really? Um, no".
5. The Broncos don't let the football team get "distracted" by contributing to the site. It's purely run by the front office. Yet you look at how many of the Broncos are on Facebook etc...they are web savvy. Having them actually contribute to the site would be a massive incentive for fans to be involved and watch it.
And seriously, Points 2-5 would probably be resolved if point 1 was different.