Yes, I think there should be doubt. You're trying to compare Los Angeles' level of urban development with that of cities that were established as major urban centers for MUCH longer than Los Angeles.
Los Angeles' prewar built environment is not all that impressive, in comparison. It's just a function of age/era of development.
LA's urban environment is certainly distinct from the cities you mention. But forget about comparison to the "big 6" cities that you mention. Los Angeles doesn't even have the built environment of smaller city like Pittsburgh:
