15 or 20 years ago FMC and BAK-4 were only found on top quality binoculars. People forget that there were a lot of other parameters that made these binoculars the absolute top. Brands like Vixen and Swift marketed (and continue to do so) several sub-top models which are really very good, yet are not FMC+BAK-4. I take my Swift 20x80s as an example of these: they have BK7 prisms, and are fully coated (not fully multicoated), yet are a solid performer and have a quality construction.
After checking with other RASC members in my RASC Halifax center we all agreed that the optics in our Vixens, whether they be binos or scopes, were very good but the common thread was that of an uncoated surface.
Nowadays, unfortunately, FMC+BAK-4 are no longer the signature of a top quality bin, and there are many mediocre bins demonstrating that, despite being FMC and having BAK-4 prisms, they can be outperformed and/or outlasted by bins that do not.