Complex sentence: They help form the stereotypical image of a "suburban America," and are generally associated with the American middle-class; however, some residential developments can be reserved only to the most wealthy, including gated communities with multimillion-dollar homes.
Split into simpler sentences: They help form the stereotypical image of a "suburban America," and are generally associated with the American middle-class. Some residential developments can be reserved only to the most wealthy, including gated communities with multimillion-dollar homes.