Note that zoning in NYC requires the step backs that you see. It allows the full building footprint to X height (based maybe on the width of the street), and then is based on an angle formula, where for every additional Y feet requires a further setback of Z feet, resulting in the stepped-top towers that exist all over Manhattan. Like all zoning, it claims a cute origin story (allowing sunlight to reach the street), but also had the motivation of keeping rents high by limiting additional construction.

From https://old.skyscraper.org/zoning/, on the reason for the support of zoning in Manhattan:

"There were two major causes for this shift, both rooted in the drive to stabilize real estate values. The first was the concern about overbuilding in lower Manhattan, both in the increased scale of such mammoth new structures as the Equitable Building at 120 Broadway and in the rate of vacant office space. The second was the lobbying of the Fifth Avenue Association, a powerful group of merchants, hotel operators, and business interests that was organized in 1907 to fight the spread of loft buildings into the fashionable retail district north of Thirty-fourth Street."