Given the average price for an NYC apartment at north of $3k, the cost to a landlord of complying with the law even once looks significantly higher than the cost of the paying the fine.
Remember, broker's fees don't go to the landlord. They go to the brokers! The only reason landlords use them is because they're free for the landlord.
It's absolutely cheaper for the landlord to hire a service than to pay a fine.
What's more, the way it's worked up until now the landlord has many brokers to choose from. And brokers (especially in NYC) will have at least a dozen different folks who will want pretty much any decent apartment. Which allows the broker to charge outrageous fees because most landlords don't want to deal with the hoi polloi, just the folks vetted by the broker.
As such, the power asymmetry between renter and broker was astounding. Changing this will be good for the renter, that's for sure.
Brokers won't be able to get as much commission per apartment because the landlords will put the brokers on a flat fee annual retainer or something similar, because they have power (because they control the available inventory) to choose which broker(s) to work with.
All in all, it won't be so good for the brokers. Too bad. So sad. /s