There are a few factors as to why the houses arent selling as well.
Main one being they cant use for profit in the future.This was the main reason people rushed to buy houses in previous patches.
Because fcs got first choice its mostly small plots left.A lot of players only complained about housing situation not because of the lack of houses as such but that they only wanted medium or mansions.With all the mansions and mediums gone half of them arent bothering.
The other reason i think is a lot havent realised yet that the way the current system works owning a small house will give them first dibs on getting a larger house next time round with house relocation.
There is also the factor that its Tuesday and a lot of people have jobs and arent home from work yet.