One of the many ways I am fortunate in my work is that I have a lot of control over what books I sell. I run the book section within a very good independent toy store. (The website, however, does not yet include our book department -- it's still building.) The store's book section is as big as a medium-sized children's book store. We stock thousands of books, so I can't say that I love every one of them. But I like the vast majority of them, and I can do things like deciding not to carry any of the dreaded Berenstain Bears. We do carry some books related to television shows -- a few Sesame Street books, some Dora and Diego, Thomas, and Caillou. The main place where I concede space to Disney princess junk is in the activity section: we carry $2.99 coloring books, and some sticker books. Also one or two of the older Barbie sticker books. C'est tout. It's too bad that a store that sounds as good as the one you visited feels they have to sell the branded books. It may be a way to drive more traffic into the store, or it may be that they feel they want to offer as wide a range of books as possible, or maybe they like them.
One of my little rules of thumb about what to carry -- not always followed, I confess -- is to stock books that the writer felt inspired to write. As opposed to books which marketing departments commission because they believe they'll sell. When you get into chapter book series that go on forever, that becomes fuzzier territory. But those books without authors listed on them, and with the little TM on the cover -- they come from market research.
Moving on to the Berenstain Bears. You called them preachy, which I think is a good word for them. I think they often choose good topics -- ones which parents want to discuss with their children. Manners, TV, anger, bad dreams, junk food, etc etc. Sometimes I think they miss the reason a particular topic has an emotional impact on kids. But even when they get it right, they're just so clunky. Often there are better books on many of the Berenstain topics -- they're just not obviously labeled in a series.
Just got to Maine, by the way. One hammock is already up, and the second will be by tomorrow. We're all ready to lie around reading in between days canoeing on the river.