There's also the concept of a loss-leader, by the by... a product that might not do well in and of itself, but ignites future sales. For example, the book that is, to many, the Holy Bible of RPG suppliments, Aaron Allston's Strike Force. The print run it had wasn't the largest, but the effect it had was magnified several fold as the lessons and concepts it imparted went through group after group, having an impact that far outweighed the run.
A similar effect can be found from early FASA products, including both Battletech and Shadowrun, where thick, well-laid-out universes that were, as noted, THICK, with detail, not only sold themselves well, but similar lines, and then deformed the market as people demanded similar products from other companies.
Now, I'm not saying Street Legends is similarly deformative, and I'm damn sure not going to compare myself to an Aaron Allston or NIgel Findley, but the core concept is that, even from a business perspective, you can do well with a product that breaks even, rather than turns a profit (Or, in rare cases, you can do well even if it turns a loss!) ... but you'd much rather something be a hit both in terms of quality and in terms of finance.
Thusfar, the Street Legends books have been fun, cheap, have been enjoyable for the players, and haven't tied the writers down (There's a finite limit to how many writers are active at once on products. Street Legend write-ups are things you can do during a "cool down" or "warm up" period, or as a way to unwind a bit when stressed. Darn handy as an outlet.)
That said, there's room for improvement. Getting the gears and stats lined up to make everyone happy won't ever happen, this is a given, but actual mechanical flaws have crepped in for many write-ups and that needs to be looked at. I don't think that we have a true 'numbers guy' that goes over the system with a fine-toothed comb. Mr Hardy's probably the closest in that regard, but his plate is a wee bit full right now, as you might imagine. No idea if there are plans for a "Crunch Editor" to make certain that all the numbers are in proper order.
Onwards and upwards!