Well I don't think that would make a difference...nobody really cares about SC3 anymore, but SC2 is still liked by a lot of people. As Shiver and I discussed in chat once, there's actually a good number of gamers who like SC2 (almost everyone who plays UQM is impressed), they just don't bother with our community, which is understandable.
Here's one thing to think about: in the late 90s/early 00s, space games in general (not all sci-fi, but games that mostly place in space) kind of imploded. Space flight sims pretty much completely died off, and then Master of Orion 3 was a huge flop. Even Star Wars didn't get any games set mainly in space for a long while...if something as big as Wing Commander didn't have a chance, how could Star Control? This is just speculation on my part though.
Recently they've made a little bit of a comeback with games like Galactic Civilizations 2 and Mass Effect, but a lot of time has passed now since the last SC and even more since the last good one. Now Mass Effect has some similarities to Star Control and I think its success shows there's a market for games like SC (and the fact that it gets compared to SC2 sometimes shows SC2 hasn't been completely forgotten), but unfortunately Activision isn't a company to take risks.
For awhile I hoped that SC1 Genesis would make it to the Wii virtual console and raise awareness of SC, but I don't think that'll ever happen.