You can't be saying the reviews of SFC3 were accurate. Most were spewing forth carbon copies of the press releases. Several mentioned missiles in the game, and almost every single one I read contained some information about the game that was just incorrect. Not to mention the fact that sometimes it's reviewer specific. I believe it was gamespy that did a review of Disney's Treasure Planet and slammed it hard for being a space combat game but stuck on a 2d plane, and so forth. Sound familiar? And yet their review of SFC3 took none of these same things into account when handing out the score. I don't think any of the SFC3 reviewers spent much time playing the game at all. Most of the time, when reading them, it seemed like they booted it up and saw the pretty pictures did a couple of missions and put the game away. Anyhow, I would be willing to put a lot more weight on what the reveiws said, had they not been so wildly inaccurate on many things.
In addition, I'm not sure how giving the game a patch would have helped it along in sales. And a demo? Well maybe, but the combat is just too simplistic, it might have scared away as many as it brought in. Even still, I'm not sure where this massive silent majority of people who loathe SFB in the game and are longing to have a Trek game without it are. Surely they must have noticed the label on the box advertising that the game didn't use SFB mechanics. Most people buy the game, not caring what's under the hood, they just want a good gaming experience, imho.
I think another thing that may have really hurt the sales of 3, is Taldren's history of buggy games that take eons to fix, or never get fixed. People started to get the name SFC tied to "could be fun, but never really worked right" in their brain. I don't think a pared down demo of SFC3 would have helped that mentality very much.
As I said, I don't care if a game is SFB, but I think we would probably have been better off if 3 had been more SFB based, as it would have meant more depth of play, which is the most important thing imho. By saying this wasn't going to be SFB based, and hyping a new combat system that would be easier but just as deep, then delivering a game with monotone combat they may have actually caused more people to cry for the old system rather than jumpin' to see what could be done next by leaving the old behind. That's the sad part.