There is a difference between place and anyplace.
Everything Disney has built is meant to evoke a specific place, a nostalgic time, etc. in order to garner an emotional reaction and connection for guests. By your metric, Main Street USA would be just fine if it was a Florida strip mall, but that's not the point. The point of having highly themed environments is in order to entertain guests, take them out of their normal lives briefly, and cause an emotional nostalgic reaction. What makes Disney unique is NOT that it is creating any new form of architecture it's that it, more than any other place in the world, is focused on recreating existing forms but using them so as to provoke a specific response by the individual.
Anyplace doesn't care about the emotion, it doesn't care to place the individual in a specific time or place. It is fundamentally devoid of such things. It doesn't care about style, it doesn't care about detail, its functionalist to an extreme. A Hobby Lobby store or a Walmart looks basically the same anywhere you go. It doesn't matter whether it's in Dallas or Atlanta, odds are that it'll look the same. As such the buildings and the environment they exist in do not provoke any kind of emotional response, or at least a response on par with the ones Disney employs.
Disney isn't inventing new architectural styles. It isn't on the forefront of architecture, but it's not trying to be. Instead, Disney has historically reused existing styles in order to recreate a specific feeling of place that transports the individual to somewhere else. Somewhere they can't go. As a New Orleans native, Port Orleans is nowhere close to what living in NOLA is actually like, but it properly evokes the feeling and the romantic idea of New Orleans and Bayou country--which is the point. Disney isn't trying to recreate reality, it's trying to build a romantic and nostalgic idea of a place.