Media coverage of Boston teams in general is not great outside of Boston. I think a major reason is NY is the sports network center, and they consider Boston a sports rival. Especially in football and baseball, with all the pro Yankee bias and Jets adulation (Goodell is admittedly a Jets fan--it showed in deflategate). The Celtics have built up media hostility in LA, Philly and NY from their successful rivalries over the decades with the sports teams in those towns. Stern, a Knicks guy, always had it in the for the Celtics--refusing to take Lewis off their cap when he died. He also didn't lift a finger when Bias died a day after the draft. He had no desire to allow the Celtics to return to their dynasty days. He had his eye on growing TV markets in Florida--basing a team in Orlando.
The TV sports media these days is increasingly dominated by the biggest markets due to their ratings system, which is what their advertising revenues are based on. That would be NY, LA, Chicago. You can see it especially in MLB Network, where it is Yankees-Mets half the time. TV pretty much controls the major sports--setting the schedules and times, etc, out of necessity. They ( or we) are the source of all those $millions going to the teams and the players.
I think a lot of the fan hostility is media-based. But look at the negative reception Goodell got in Philly. He was booed by thousands for three days. I think the Patriots have gained respect from fans everywhere from their great super bowl accomplishments. Overcoming adversity. The Red Sox already have a national following from their multi- championships. What the Celtics need to gain that level of recognition is some championships. 10 years is too long, Danny. Nobody remembers the Russell or Bird eras.