The only profession I can think of where the ACTUAL PROFESSIONALS argue AGAINST things that make one well qualified, experienced, and highly trained.
WHY would pilots WANT someone with less than 1500 hours flying an airliner?!
This. Let's not forget that flying a clapped out Baron full of blood specimens or any other 135 IFR gig has required 1,200 hours since forever, and actual insurance requirements were far higher. 1,500, if not much higher, was the defacto regional/commuter requirement since they became a thing, and nobody squawked about that.
The ATP rule isn't about 1,500 hours, per se. Heck, getting the ATP before the rule wasn't really about 1,500 hours, it was about HOW you got from 0 to 1,500 hours.
Going from wet commercial to watching the autopilot fly and having the captain make the decision does zero to make a good pilot. It's just rote memorization. Then all of a sudden you're in the left seat, with no idea how to say "no". Even a CFI learns that lesson early on.
Its a consolidation process, it's a learning process, it's a "get to know thyself" process, and yes, for the industry, it's a couple years long vetting process. If you can run the gauntlet, you're probably pretty stable.
This isn't an either/or. It's not like a single person is safe at 1,501 whereas at 1,499 they weren't. But that's where the statistics show that you have a pretty good chance of not being a complete dip• where you have the potential to hurt someone, including yourself.
FWIW, every single pilot I've met that was opposed to the ATP rule had some vested interest in it being otherwise. Kid doesn't want to be a CFI or work himself up or has a financial interest in some school somewhere selling the dream. Very rarely is it some rando just spouting off.