So far as the niche market goes, I note that the FCC's most recent report (Feb. 2006) notes that DBS subscribers make up 27.7 percent of the multi-channel video programming distributorship market, while cable makes up 69.4%.
Interestingly, though, DBS marketshare increased 10% from 2005 to 2006, while cable market share dropped approximately 5% over the same period.
http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-263763A1.doc
Niche market? You be the judge, but closing in on 30% of the market doesn't seem like a "niche" to me.
DirecTV is a niche market. Satellite may be, but that isn't what I said. DirecTV makes up approximately 60% of the satellite market, which translates into roughly 16% overall. That means MLB would be willingly decreasing their available subscribers by a factor of six. Why the hell would they do that?
EchoStar has been gaining faster than DirecTV, by the way, so I'm not sure DirecTV is really the beneficiary of overall DBS gains.