The Sox and Bruins appear safe from the RSN collapse for the time being. But what of the Celtics, on Comcast's NBC Sports Boston, whose programming outside of Celtics games and related shows is dire? There's a Patriots talk show, but (of course) no games, and "Felger and Mazz," a radio show from Boston's also-ran sports station, WEEI. After that, various tout shows, umpteen thousandth reruns of the highlight film of the Celtics' last championship, and "Boston Sports Tonight," which repeats six times after its first airing. How long can this weak lineup attract the advertising need to keep NBCSB afloat, especially amid cord cutting?