NYC Real Estate Expert on Office-Apartment Conversion Economics - WSJ

The Wall Street Journal ran a piece on the current economics of office-to-apartment conversions in NYC and how the mayoral race could have an impact. Some of the math has me scratching my head as there are some assumptions that don't make sense, at least on first reading. Specifically: >>These projects cut the amount of leasable space in a building by 25% because residential tenants don’t pay rent for communal areas such as corridors, lobbies and elevators the way office occupiers do. This eats into the amount of space that will eventually generate income for the landlord.<< How do tenants’ rents collectively not pay for everything, including common spaces, maintenance, upkeep, etc? Is there some statutory limitation on how much an apartment can cost based on square footage? Is it more of a practical thing, that in a redone office building, where there may be more common space than in an apartment building, there’s a market-based limit on how much people will pay for a place? Or maybe it’s the rent stabilization of 25% of units, so effectively, they get left out of the rising costs. Whatever the case, I need to talk these and other numbers over with someone familiar with the practice in the NYC landscape. Thanks in advance.