As Frankston and Frankston North gentrified, developers started buying out the homes of the local riff raff who then moved on to cheaper inland areas nearby - Carrum Downs is one such neighborhood.
I'm not saying Carrum Downs is bad value, there are many lovely town houses there and prices will gradually move up with inflation; goodness knows they surely cannot fall as they are already off a low base. But it's not a suburb that has gentrification potential. Great for a PPOR, if you don't mind the bogan neighbors with their powerful new Holdens. But virtually no development potential.