Ok, I'll bite. I think it's possible to become a safe and professional transport pilot regardless of how initial training was conducted (military, ga, traditonal ab-initio company sponsored/discounted cadet programs, MPL, and 0-atpl self funded), for those who get hired by a reasonably well managed airline.
At the same time I keep wondering if people who were accepted into a training that is paid for by others, fully or partially, have faced more rigorous selection earlier?
As an example, i read that in Norway a public university offers a 3 year degree in aviation now that gives you a Cpl-ir etc and fATPl, and some added academic knowledge as a bonus. Tuiton is symbolic, 200$ a year or so. Needless to say, seats are limited, lots of people apply, and selection is rigorous. As far as i understand graduates dont struggle to find a job. Same is generally true for military training.
The more you pay for your own training, the less selection there was to begin with, and then when you'll have to face that selection later, there's a risk you'll fail...after having paid a substantial amount of money (and hopefully you wont fail by making a hole in the ground, but just not get hired).
Most of these pay-for-a-license, pay-for-typerating, and pay-to-fly schemes are just a way to postpone selection, in my humble opinion. That doesn't mean that those who go through that way of training can not be excellent pilots, they could have passed the same standards others did, we just dont know, so possibly more selection is needed, for some of them.