I would like to point out that it's not really fair to compare an ab initio 200h pilot vs a GA pilot with 1000h+ during supervision on their first airline job.
Say you give the former the same line flight time it took the GA pilot to get these 1000h, how do the two of them compare now?
I think the point is not on who is better prepared during supervision, but after a similar amount of total flight time.
Anyhow, if these schemes are in place, and working, and no accidents have resulted from them, the system is probably not so bad.
A different issue is what expectations has each and everyone of us about their flying career. That differs clearly from pilot to pilot.