"This type of conversion in a reasonable barometer of cultural shift taking place in a neighborhood"
Ya' know what else is? The race of the people on billboard advertisements.
When I'm out of town or in some strange area, I can always go by that to tell when I'm getting into a different neighborhood.
However homogonized the gvt or various other groups insist we view our cities, I'm convinced the ad agencies must actually have racial maps in their offices.