Adie
First Officer rates seem to be about £20k-£35k depending on where you end up and what you end up on. Captains rates seem to be about £50k-£110k.
Assume you will spend >£20k on CPL/ME/IR even if you do most of it in the US. Then consider you may have to spend another £5k to become an instructor. Then assume you will be bonded or have to pay another £15-20k for a type rating.
The reason so many people do this is because life is not a dress rehearsal. If you dream about flying when you go to bed, you just have to give it a try... whatever the odds... and if you dont get a job, you can at least say that you gave it a try.