That's part of what I said . . . posters are unfortunately a redundant form of communication/promotion. I still think they should be there, but those who are more utilitarian minded don't see the point.
There aren't that many posters from NYC because:
A) I'm a lazy piece of shit
B) Promoters and venues don't want to make the investment
C) Not many places to "legally" poster.
D) Strong word of mouth/music press replaces the function of posters.
E) NYC thinks its too cool for itself . . . and sometimes it's right.