The thread wasn't really meant to solicit business ideas, just a catch-all for anyone who wanted to talk about this kinda thing, but I have to say, while this might be considered conventional wisdom in most parts of the country, this is somewhat ill-advised for NYC.
Real estate prices in a lot of cities are artificially inflated by asian investment imo. When the average working couple can't pay off an average mortgage without skipping lunch for 30 years and the interest repayments alone approach rental income, it's time to extend a middle finger to the whole shitshow.
This all ties in to my Dead Parents Theory of Home Ownership Because The Math Doesn't Work Otherwise, but I'll spare you. People who advise existing in a leveraged state never had a fat kid jump on the other side of the teeter-totter.