I know that in greater NY/NJ and probably LA there are dozens (if not hundreds) of options for shopping for kosher food.
Here in Chicago we have fewer options. Skip the background below if you know about Chicago.
If I simply need kosher products I can always go to a local chain store (Jewel or Dominicks) or independent which will no doubt carry the usual array of hechshered products and may even have a small "kosher" section. If I shop there, then I probably also purchase much of my produce, eggs, milk and household supplies there too.
If, however I want meat, cheese, fish, shabbat paraphernalia, deli items, prepared foods and unusual items I go to a kosher store. Amazingly, there has been only ONE "all-kosher supermarket" - we have a number of smaller all-kosher grocery stores (the Kols), 3-4 short aisles with an extra room for just about ever.
A few years ago the Jewel chain (part of Albertsons) remodeled a store, adding a kosher department - deli, prepared foods, sandwiches etc., in the suburb of Highland Park. Apparently it was successful because later they added a packaged kosher meat (Rubashkins and Empire), packaged cheese and greatly expanded kosher section at a second store in the suburb of Skokie. That worked so well that this month they have again remodeled a store this time in Evanston on the Chicago border - which now has a very large supervised kosher department/section (prepared foods, cakes, deli, cheese etc. etc), is long rumored to be opening a Chinese take-out section and expanded an already large kosher section.
This week a letter was sent to just about the entire observant community over the signatures of much of the local Rabbinate warning us against the evils of occasional low prices and convenience and a non-shomer shabbos store. They declare that by shopping there we will drive the others store(s) out of business, resulting eventually in higher prices and even suggest that there might be kashrut concerns.
Which brings me to some questions. What is the experience of those of you who live in NY/NJ or LA. Has competition from chain stores driven Jewish stores out of business? Has kashrut suffered? Have prices increased or deceased. Any other issues or thoughts.