With respect to m'lady and all else, there is a HUGE extent to which marketing drives not only what is purchased but also what is available. And these parameters cannot logically be discerned remotely. It's logical to the marketing conspirators, but never to the customers. And it varies by neighborhood.
IOW, for example, if a store's primary demographic is led by marketing and marketing is pushing liquids, that's what the store will have and that's what the customers will buy. Whether it's good for them or not, they will BELIEVE it is.
OTOH, if marketing is pushing liquids but the primary demographic still doesn't like them, the store will stock powders because that's what sells. And again, none of this can logically be predicted from one neighborhood to the next.
Yes, it most assuredly was a great deal simpler a generation (20yr) ago. Before marketers adopted the "divide and conquer" method. If you want an in-your-face presentation of D&Q, watch politics. The exact same marketers who sell you detergent sell you national "leaders", using the exact same methods.