IMHO Winn-Dixie just had an image problem in Dallas, many of its stores were older, and it just didn't have a 'hip' image(for lack of a better term) in the Dallas area. Plus grocery margins have always been tight.
Yeah, Target has really come in like gangbusters. Every new store(and many older expansions) adds a grocery section, and is marketed as a 'Supertarget'. A little pricier and not a huge selection, but the quality is high, a nice mix of specialty items and produce, so the all-in-one convenience is a big plus. Walmart is also moving toward superstores, with more selection and rock bottom prices. Personally I don't see how Minyards will be able to hang on for long(same older image as Winn-Dixie), and wouldn't be surprised if Albertson's pulls out(newer facades and supersize, but the stores are often trashy/dirty inside).