I could easily see the bluey market blowing up. I think people just haven't really got enough exposure to them yet. Once you've seen one in person, observed it a while, held it - they really are just about impossible to resist. I know when I was younger and looking at buying my first larger lizard my buddy Mike showed me one of these and I forgot about all the monitors I had been researching in the blink of an eye. Needless to say, my next reptile purchase was one of Mike's newborn northerns.
That said, I don't think people should make purchases based on what's popular. Work with whatever blows your hair back and enjoy your animals. You'll be happier and the animals will be happier because you will take better care of something you personally enjoy.