quality foods (looking at you Royal Canin, Bil-Jak, and Science Diet), making obscene profits selling near-Dog Chow level foods at boutique-level prices ... are losing market-share fast to brands creating lower-margin but much higher quality foods (most of what's on this list) due to people getting better educated and caring more what is in the foods they're feeding their pets, and mainstream stores responding by stocking more and more of these products.
In AZ recently Pet-Smart has started stocking Merrick, which is of great quality, and for a while now they've been adding more and more high-end, high-quality brands. They still have only a few 'boutique-level' brands available, but their top-end offerings are moving up, I'd bet a few more of those type of brands (like Call of the Wild for example) ... are coming.
If there's really a problem I suspect it will NOT be traced to foods being generally 'grain-free' but rather to some ingredient that's commonly substituted for grains (i.e. Wheat and Corn) such as Millet, Barley, Peas, Lentils, or Potato (Sweet or otherwise) ... don't get me wrong, we need to get to the bottom of it, but in the meantime I'm not going to suddenly start feeding my cat almost-certainly GMO GRAINS (nor would if I still had dogs). I'll take my chances continuing him on high-quality foods and let the chips fall where they may.