We have a handful of exceptional pilots who started in the cabin, They're the best, really admirable people, but very few make it.
None of them got a sponsorship, I paid 200£ just for a direct entry exam. I think companies should pay for their own selections. So only go to selections if don't have to pay!
It also all gets down to flight schools having strewed up their prices, with the Euro and after low attendance due to 9/11. Even airlines have started to make money on selling type-ratings and through partnerships with flight-schools to make money even on new entrants, down to the loans and interest rates.
I believe modular training shows great motivation, allows great flexibility, an international path and compared to big schools its cheaper, but self sponsored is still a huge risk. While doing my PPL and flying in the cabin, I'm having a lot more fun then in a quick-bleach school and I'm convinced that I can fly up front some day.
I've also seen guys with an ATPL work as cabin crew and finally being fired. It's not all rosy, but down to personal will, attitude and flexibility.