Fire codes at the time required wide paved streets to act as fire barriers. You get double benefit when you can get your fire engine to the desired location by

Fire codes at the time required wide paved streets to act as fire barriers. You get double benefit when you can get your fire engine to the desired location by that new fat street. And then again reinforced concrete also became available around 1900. So yes, the code is only small part of all that. But I'd claim it's significant part.