I wouldn't say BrickForge is THE ONLY ONE that covers multiple themes and eras
I would say that BrickForge is the only one that covers multiple themes and eras "as far as molding (or plastic accessories) goes"!!
I would pose that it is difficult to separate cloth accessories into 'themes and eras'. A trench coat, for example works within a wide range of themes, same with cloth pauldrons, tunics and robes. It's much more difficult to visit the MMCB website and make a statement about the products covering a wide range of 'themes and eras'. With plastic-injection items it becomes a bit more obvious as to the distinct purpose of the piece, hence easier to make such a determination.
Our booth is pretty much non-stop at the shows and we always have someone from LEGO corporate at our booth checking us out. Our online business is just as busy and again, we ship several orders to Billund, Denmark. They know who we are and they love us because we provide feedback as well as a virtual playground where they can independently observe the success of various 'theme and era' pieces.
No doubt we helped push out products they've been sitting on for years or never thought up in the first place. To their credit though, their designers are just as creative as us and have probably been pushing for certain pieces that are just now making it to market due to the economy. I can't say much about the new collectible minifigs, just that their availability is LIMITED and their accessories are NOT an indication of future LEGO themes. Of course anything can change, I suppose. I might guess that a possible Greek/Myth theme might be based on how well Atlantis sells.
If anything, the new collectible minifig series will simply make more people aware that BF exists and when all those Black Berets and Gold Greek Helmets have sold out on BrickLink for $12.00 a pop we'll still be around offering similar products for much less, in many more colors.