My first house in Flatbush cost $35,900 in 1974 when I was earning about $10,000 a year. Typical Flatbush houses ranged in price at that time from $50,000 – $65,000. Keep in mind the mortgage rates were 8.5% in 1974 and as high as 17% in the spring of 1980. Back then real estate taxes were much lower in NYC than in the suburbs but have now quickly crept up. Two bedroom apartments were available for under $300 in those years. A couple earning both minimum wage could afford an apartment and middle class families could afford homes.
I only have observations, not answers. I don’t see the end of the Flatbush community, but the graying of it which has more of an impact on the yeshivot than the shuls. Perhaps as large numbers of aging homeowners downsize house prices will drop. The young Sefardim are in the same predicament as the Litvish. Not all Sefardim are wealthy.