Satellite radio and HD radio sound horrible?

This is i guess going to be more of a discussion than a question but I wanted to get it out there. I work for a Ford dealership in their rental department and am in and out of cars all day cleaning them, gassing them up and chauffeuring people around. So I get the opportunity to listen to all these formats on a regular basis since Sirius is activated free for the first 3 months all our cars have it and we go through them pretty fast. I couldn't help but notice how horrible SiriusXm and HD radio sound. They both sound very tinny and digitally compressed unlike standard FM which sounds more natural (if not a bit scratchy at times) I still enjoy listening to all the content SAT has to offer (we dont have a rock fm station in our area anymore so I enjoy listening to SXM's Octane.) And I know its got nothing to do with any settings on our cars and some of our Lincolns have kick *** sound systems which ironically make the satellite and HD radio sound worse lol. I dont see how anyone can justify spending like 13 bucks a month for Sirius. And I remember hearing all the commercials on HD radio claiming it was comparable to CD quality, psssh CD quality my ***. Anyway why does it sound so bad? I remember my old Chev Tahoe had XM radio (before the merge) and it sounded fine. What changed?