Pronoun reference words can sometimes be confusing but if you google it you will find lots of information about it. 
 
 
They refers to no-one but it also refers to people.  No-one, in this context, means people. 
 
No-one (not one person) wants to buy homes there  because ...
People do not want to by homes there because... 
 
Re no-one/someone - when the gender is not known you can use their or they 
 
Somebody has left her/their purse in the ladies restroom (gender implied)
 
I�m missing one class text book. Some one has forgotten to give me their book (gender unknown)
 
Somebody has left their flash drive in the computer 
 
When no-one attends the meeting, they miss out on vital information
 
Cheers
 
Jayho