Calling the Star Wars fanbase discerning and unforgiving is almost laughable. You've clearly forgotten "A Star Wars Holiday Special", "Star Wars: Droids", "Star Wars: Ewoks", "Caravan of Courage: An Ewok Adventure", "Ewoks: The Battle for Endor", and many, many more. The 80s and 90s weren't fallow for Star Wars content, they were fallow for good Star Wars content. The crap put out for almost 2 decades, before the crap of the prequels, in T.V. shows and movies alone, should have killed any "discerning and unforgiving" fanbase. It didn't. Because that is not what the fanbase is. It is rabid and forgiving to a fault.
And none of that even mentions the crappy video games, of which there are many, the crappy books, of which there are many, many more. There is absolutely nothing discerning about Star Wars fans. And the miles and miles of crappy plastic toys that followed the original action figures and ships only supports the point. They will pay for anything related to Star Wars, regardless of quality, and pay over and over as we have seen for 40 years.
Box office isn't important? You're right in a sense. Box office doesn't tell you if a movie is good or not, but it does tell you how many people will pay to see it, a pretty good indicator of the breadth of the fan base. And there are only a few as large, as healthy, as willing to spend money, as the Star Wars crowd.
Any other analysis flies in the face of reality.