My reasoning is as follows:
I want to do that research for pleasure, not for a title. The possibility of trying for a career in academia would be nice, but I see it as some sort of a "bonus". In the first place I wanted to do a PhD because I dreamt of good working conditions for that research. But with that estimated 8%, I realise that the working conditions would not be that good - I can picture my hair turning grey in two days over money-related worries.
So I've pretty much decided to carry on with that research in my own time, keep the job I have now, and apply again and again.