There could be other factors, like you say, which might be the reasoning behind the sale. Given the current state of energy bills and my new mortgage deal, I can certainly sympathise if it is the case!
Having said that, the problem, in my opinion, is that the 300h (IS or RC) is a much better car for everyday driving, so why go for the niche product when the 300h is so readily available? From the couple of days I had a IS200t, I can say that I don't think it would grow on me either.
So, for people that do buy them, either there is something about the 200t that they prefer or they find a deal on a car that they like that is too good to ignore.
Either way, shame really as the 200t could have been a fun alternative to the hybrid models.