My wife is from Chicago, and we lived there a year and a half. I'm wondering why anyone needs a restaurant to have Italian Beef or Chicago style dogs. This is pretty easy to do at home.
I haven't seen much in the way of food that I can't do better.
In my opinion (and other opinions will vary) it's kind of like the hot dog carts in New York. You can make 'em at home, but the experience just isn't the same.
The Italian Beef however...sure you can try to make it at home, but it really is impossible to reproduce the flavor of Italian Beef at a Chicago restaurant. The spices used, the pot used, the length of cooking time, all of those things are practically trade secrets.
Yes, one can do those things at home...I do it when I have to...the point being, when we are out, and have a taste for Chicago style dogs, and italian beef and sausage combo sandwiches, its nearly impossible to find a place that has what we want....of course, I can cook them up myself if I have to, but when we are out for a day of fun, and I dont want to have to go come and cook, and we have a taste for our Chicago specialties, its darned hard to find them...at least out here in the Pacific Northwest...