A lot of these XX years to JB have to do with the aviation environment at the time. We are not in the same Environment today that existed 20+ years ago. Yada yada yada, pilot shortage.
The reason these programs exist is because of the airlines need for pilots and the pilots need for training. If just one of these two factors was gone, this program wouldn't exist.
According to the JB Profile on APC, the most junior captain was a Feb 2015 hire. Since zero to Regional FO takes about 2-3 years for a motivated pilot, it's conceivable that even pilots NOT using the ab initio program could potentially be hired within 4 years of their solo flight.
That said, I'm not a fan of these programs. Pilots can get flight training MUCH cheaper than 110k/125k using FBOs and Flying Clubs. Goodness knows there are plenty of CFIs looking for hours willing to do work cheap on the side.
So you're basically paying for the benefit of skipping the regionals and going direct into JB. I won't lie... that's a pretty big benefit. I just can't justify the 70k-80k additional expense for it. Mostly because I loathe debt.