I've reached a similar conclusion. My salary as a police Inspector puts me on a par with what a Captain with Flybe earns in their first few years of command.
I could afford the training. The killer is earning nowt whilst you do it, plus a paycut, and let's not mention giving up the pension of two thirds final salary on retirement at 51. Add the current job market in to the mix and it's not a goer.
I have a mad idea I could do my ATPL when I retire. Arguably I could give an company such as Flybe/Eastern/similar up to 9 years service. Too old for a second career?