Apparently many people are leaving Boro Park because according to Zillow home prices there dropped over 9% in the past year and are expected to drop another five percent over the next.
The non-Jewish neighborhoods are also seeing and looking at future declining prices but not as steep of a drop as Boro Park.
I also spoke to a frum realtor in Flatbush a while back who said that two summers was probably the peak for Flatbush. The people looking to rent or buy in Flatbush are no longer willing to pay those prices anymore.