Minimal Landscaping in Urban settings

It is only something I noticed doing some of my research for 3D model purposes.  Of the places I have read about and seen (and believe me, there are a lot of places), I have noticed fairly minimal landscaping in the streetscapes.  Some streets do have some of the basic items: trees and grass strips, but there are some scenes with almost no landscaping to speak of. 

Suburban placed in Urban

This stemmed from conversation about the 3D models and the general ideas of urban infill and suburban retrofitting.  A question from the discussion concerned the demolition of urban and long established environments for the creation of completely suburban entities.

"Is suburban-to-urban redevelopment in urban areas, the only option?"

I'll give a few thoughts to outline.