Again, for now only buildings that are being targets is new
Older buildings do not have to eliminate gas hook-ups by retrofitting.
That does not mean NYC buildings escape this fresh new Hell, they are coping with other mandates.
https://www.urbangreencouncil.org/content/nyc-building-emissions-law-frequently-asked-questions
Thing to remember at least in NYC vast percentage of housing are rentals. Of that nearly 60% or more falls under some sort of state, local or federal regulation. This includes rent regulations, public and subsidized housing, and so forth.
Thus whenever state, city or even federal government order commercial or residential buildings in NYC to do anything, logical course is for owners to pass those costs along to tenants. All sorts of housing cost more here than it ought to due to heavy regulatory environment, price controls and other factors.
First round of telling developers to build apartment housing with lower emissions caused them to install PTAC units in apartments instead of central heating. That was all well and good except low to moderate income tenants (and their supporters) moaned that given NY's high electric rates such households would be at a fiscal disadvantage.
There is no such thing as a free lunch. If one group does not pay their fair share, others have to pick up that end.
Vast amount of those pushing or pushed for this change live in older and most likely rent regulated or public housing. They won't be affected by these changes, but anyone looking for new housing of any sort from single family home to an apartment will be paying more.
Ironically anytime a LL tries to change heating or whatever from current steam or hot water (from oil or gas) it is tenant supports who are first out of gate saying people cannot afford to pay.