There is no theory by which less of them results in lower rents for you and me.

People move here from NYC because of lower income taxes and more space; people also move here from outside the NYC metro because of better job opportunities. Location is the #1 determinant of whether someone moves, not whether there is new housing there. This is why gobs of millionaires live in crumbling old buildings in Manhattan and parts of Brooklyn.

If you don't build the yuppie fishtanks, the yuppies will simply outbid for your housing. Don't be mistaken and think they'll simply stay away - that's what they thought in San Francisco (and Manhattan and Brooklyn), and then the rich moved into the old housing, because they care about location and proximity to jobs, not whether the housing is new. They can always move in and gut renovate the inside, after all, or the landlord does it to take advantage of the higher rent they can pay.