I don't know that supermarkets will necessarily compete with a well-done, personalized-service wine store, like Table Wine is. Since it takes me a good half-hour to walk to table wine and back - when I have guests over I sometimes have to stop at one of the less pleasant liquor stores and just grab a bottle of whatever's there (Yellowtail has often become a default table wine because of that). Also, as far as hours go, Table Wine is not that easy for me - by the time I get home and take the dog out for a potty break, many neighborhood stores, including Table Wine are closed. (If it closes before 8:30-9, I'm not gonna make it most nights) If I could buy a half-decent bottle of wine at Trade Fair or another supermarket that is open (I don't know if the 24-hour Indian groceries near me would choose to sell wine) as I pick up something for dinner, I would greatly appreciate it.
I think that the supermarkets will take some of the wine sales from liquor stores, but a well run wine store shouldn't have too much to fear. I know that where my parents live in Virginia, they often buy wine at Whole Foods or Harris Teeter supermarkets, but they also patronize Best Cellars in Arlington, which seems to do just fine despite the availability of wine in local supermarkets.
http://www.bestcellars.com/aboutbc/stores_clarendon.cfm In many ways, Table Wine reminds me of Best Cellars in that there's a carefully chosen small selection of all-good, not-too-expensive wines - curating and organizing the selection makes all the difference in the world.
Table Wine seems to be doing the right thing - having tastings, explaining wines - building a community around its wine store. Plus, once supermarkets can sell wine, can't wine stores sell crackers, cheeses, and things that are frequently eaten with wine? Wouldn't it also allow them to sell specialty and crafted beers as well?
Here's another article about another VA-based wine store, The Curious Grape, which also exists quite nicely amongst thousands of supermarkets selling wine. (I point out VA since that's where I have experience with wine in Grocery Stores coexisting with wine stores...I know California does it too, and specialty wine stores are everywhere there)
http://www.washingtonpost.com/wp-dyn/content/article/2010/01/14/AR2010011401618.html