This is not true? Lots of urban areas can sprawl, not least because of car centric planning (big car parks between islands of actual land use; roads built to ease the traffic of roads; urban 'islands' of tall and dense occupation connected by road with slivers of green in-between that don't serve to actually offer a natural environment. Kuala Lumpur features all of these, for example) but also as economic centres decline and become disused and new developments in other areas spread.