How to avoid brokerage

I see a lot of flats that are supposed to be rented out , directly goes to brokers.

The security of the society also gives brokers number when asked if there is a flat empty in the building.

What is the economics behind this, do owners also not pay a cut to the broker for managing their property ?

How can I avoid brokers ? Is it possible to. Negotiate their brokerage .

50k brokerage is too much