If you don’t mind, I’m curious what sort of procedure and training changes occurred after the 2009 incident. The streak of no major domestic crashes (and basically no crashes at all) is really impressive and I think it should be talked about more. If the procedure and training changes are responsible for the streak we should be holding a parade or something for those responsible. Speaking of parades, I wonder what changed to make them seem lame these days. Are they just boring relative to film?
The biggest one was requiring both pilots to have ATP certificates, effectively moving the bar to co-pilot from 250 hours to 1500 hours of flying. Lots of other changes that taken on their own are small, but overall it was a pretty massive set of changes.
It's not clear whether the 1500 hour rule directly improved safety. Both the Colgan captain and the FO had more than 1500 hours at the time of the accident. What the rule did unambiguously is severely restrict the supply of new pilots to regional airlines. This significantly improved quality of life for regional pilots, who prior to Colgan were effectively making minimum wage or worse. (That may have indirectly improved safety, by making pilots more well-rested and fed...)
Another point of comparison is Europe, which has a not-dissimilar safety record, but still allows FOs to have 250 hours. That said, from what I understand, they have a very different training culture where students start in a multi-crew environment very early.
I remember reading about the typical lifestyle of a new regional pilot. Low wages, long hours, and often flying many hours as a passenger to get to work (living in Pitts, grabbing the first flight to NYC to work, etc). It sounded miserable.
Fatigue rules were changed to be more strict. Requirements for regional airlines pilots were changed to require at least a minimum of 1500 hours for both pilots, previously only one pilot was required to have 1500 hours. Standards for grading stall recovery were changed to avoid incentivising the behavior observed in the pilots in the 2009 crash.
The counterpoint is that their safety record speaks for itself. When was the last commercial airliner crash in the US? 2009?