There are a myriad of reasons for this, but you're right. Primary reason is we have only one true superstar and that's Karlsson, aside from that there are guys like Stone who are stars at this point, but I doubt you'll hear John Q Fan say they'll go to a Sens game to see Mark Stone. There's no superstar forward on this team, no one player that will draw viewers unless their fairly versed in each team's players and know about Hoffman, Turris, Brassard etc.
We're also dwarfed by Toronto and Montreal, both of whom are much bigger markets and therefore get the bulk of the headlines.
Then there's a building that was once considered pretty good, but is now a huge paperweight.
Then there's the marketing aspect. This team feels a lot like the Pesky Sens of a couple of years ago, without being branded as such.