Originally Posted by FXLAX

I think the captain didn’t have 1500 hours nor an ATP at the time he was hired at his first air carrier. Maybe the FO didn’t either but I don’t remember anymore.

Before the ATP rule, a pilot could be hired with a 250 hour wet commercial multi engine certificate (this was actually happening). Then become captain at some point when seniority allowed. Presumably, with enough train to proficiency, most pass their training. And the first time they are captain (sign the release) with dozens of paying passengers is the first time they are making PIC decisions since they were soloing during their private pilot training.

The experience you get from accumulating the hours towards and ATP is not for stick and rudder skills (pattern work). It’s for being the ONE person making thousands of little decisions, making mistakes, perceiving mistakes, fixing mistakes, making go/no go decisions, dealing with ATC, dealing with weather, maintenance, personal issues, outside pressure, aeronautical decision making, threat and error management, crew resource management, etc.

This is the real reason for the ATP rule. That experience gives you a foundation on which to fall back on to help when the fit hits the shan.