You only need enough buildings so that the reader can see where the fight is taking place.
Mangaka use speed lines... just drag and drop... background done.
(most people thing "speed lines" are to indicate something/someone going fast, but it really means it is speedy to draw the background... but don't tell anyone.)

Soooo smart... not
Is this blond one of those who stands at the bar and proclaims "I am sooo drunk" to indicate she is ready for someone to take her home?