Like all great shows, Angel was inevitably cancelled. Even though Joss and the writers wanted a sixth season (they definitely had the ideas for it, as Angel: After the Fall clearly illustrates-- no pun intended) the networks just didn't see it in the cards. Though Angel proved that it could definitely stand on its own two feet after Buffy ended, this decision was made before the second half of Angel Season Five actually aired. My guess is, the WB didn't believe that Angel would work as well without Buffy (oh ye of little faith!) and told Joss at the beginning so he could wrap up the series and make the final season a smash success. At least that was thoughtful of them to do that, so the Angel cast and crew could "make arrangements" so to speak for the end of the show. And it allowed Joss to try some crazy ideas (like Fred to Illyria) so it wasn't all THAT bad.

the networkers are douchebags

Actually the story continues in comic books, it's called "Angel After the Fall" published by IDW and the website that I get mine subscription from is www.tfaw.com, I have all of them....right from the start. I just got issue #22. And they even did "Smiletime" as a 3-issue special. Plus they published "Spike After the Fall". Check it out, you will be surprised at what happens to the whole cast.