Cincinnati Dog and Detroit Coney

I have to wonder if Detroit and Cincinnati are parallel universes.

I just read how the Cincinnati Coney dog -- sausage, Cinci chili, onions, mustard and cheddar, is being introduced in Nebraska at the Saucy Dawg Cafe in Grand Island, Neb.

The article traces its origins to Greek restaurateurs in Cincinnati in 1922.

That is so Detroit. Well, except for the cheddar and a different style of sauce.

I am wondering just how many places saw Coney Island restaurants of differing styles open up in the 1920s?