Why is that important?
First off, I have a Sirius radio. I would not like to see it go "dark" and become an expensive paperweight. I'm one of those who thinks that the star power that Mr Stern brings to the service, regardless of whether you listen to him or not, means there will be increased "Mindshare". Increased mindshare means more people considering paying for radio. More people paying for radio means Sirius may be a going concern.
Secondly, I actually do listen to Stern. Once in a while, when I feel I need comic relief, he's a great change of pace. Whether I agree with him is another matter and usually I agree with him when he speaks politically. His fixation on the bizarre isn't really for me, so I'll switch off to something else more musical and get back to work... what ever that may be. Others like that, and great, we all will be able to hear about Baba Booey for another 5 years or how the interns are getting on in NY. If you never have had a chance to listen to him talk to George Takei (Sulu from Star Trek) you are missing something that is a one of a kind experience in Radio. He has to be one of the best interviewers on the air.
Thirdly I do think that Howard Stern is worth it monetarily to Sirius. Without him, they would not have the 20 million subscribers that they do now. For each of them who do not have a permanent subscription (like I do), they are getting $20 a month. Doing the admittedly sloppy math, that means Sirius is taking in $200 million a month. It takes Sirius 2 weeks to pay for Howard's old salary for the year.
Without Howard, Sirius would probably not be a going concern, with him... I can listen to trance, disco, 40s music or Progressive/Liberal Talk without plugging in the iPod.
So for five more years... enjoy what ever you listen to. After five years... who knows.
Now if they could just get the damn DJs to shut up I could listen to the Sirius radio longer!