Well, Carl, since it is no longer 1998, and speaking as a long-time broadcasting Engineer I would have a very hard time agreeing with this generalization. It may apply to some lower-rated channels with low budgets or to SD-only channels that have not upgraded to digital audio chains, but I think the tendency even there is that things have improved greatly over the last few years.
inline_phil does have a point about TV sound.
In general, it is very compressed and with poor response at the frequency extremes.
For medium-to-large market broadcast and for 95% of cable networks audio is sent as AC-3 and is likely processed through an all-digital chain prior to that. If not, it is likely processed in a high-quality analog equipment at certain stages. In either case, frequency response is characteristically flat between about 50 to 15K, and in most cases well beyond that.
Also, one of the benefits of digital delivery is that the dynamic range is much greater, and that there is not the need for the conventional level-compression that we saw with analog TV or cable. For most stations and networks, final processing is done very intelligently and effectively, and much, much better than it was just a decade ago.
Digital also allows us to not use compression as a tool to keep levels constant, which was the poorly-implemented goal during the analog era. New equipment uses sophisticated techniques such as BS.1770-2, which aims to keep dialog at the same level, and is exceptionally effective at doing just that. The implementation of the CALM act this year coupled with this technology will very-quickly make uneven audio levels a distant memory, while preserving full dynamic range at the same time.
(And if you were actually speaking about digital compression rather than dynamic range compression, AC-3/DD is far less compressed than MP3 and has a far better quality than MP3; about the only thing that can beat it, and not by much, is DTS. If you want to hear badly-compressed audio, go to satellite radio or Pandora).
Not all sources live up to these new standards just yet, but the vast majority do. Had you made your statement pre 911, I would have to agree with you. But its 2012, and things have changed greatly, at least for the most part.