Mamdani explicitly campaigned on building more, especially housing, so not sure where you got that idea. NIMBYs show up at community board meetings, sure, but your post makes it sound like that's somehow the mayor's fault?
I'm also not sure if you're a New Yorker or not but the NYC EDC remit is a hell of a lot more than just "encourage big business". They run the ferry, for example, and other infrastructure projects