This was not discussed in your opening statement. However one unintended consequence of this is the length of time ATP cert holders will be on their rookie contract:

For example it’s not rare nowadays to see 2000hr ish or less pilots in new hire classes at a legacy, this is after spending maybe half a year at Regional X.
I think this will be less common following an age 67 ruling, for of a period as you guessed 2 years.
Furthermore the whole “skip the regional” straight to LCC Hotshots will also will likely decrease in volume.

But is that really such a bad thing? Both individually and collectively.

All other things being equal the people on the low end from regionals going to majors now have basically maybe 1/4 of the experience of those 9-10 years ago and are being paid about 240% more.

Most people reading this know a tremendous amount of learning takes place at the regional level, the kind that you can only get by doing it. Regional flying is more conducive to learning and developing than LCC flying. 3-5 takeoffs and landings a day, but also 3-5 Sid’s and stars, 3-5 ground ops, large B airports and occasionally uncontrolled airports…….and of course less time at cruise to talk about how smart you are.

While I’m confident these 2000ish pilots are just as if not more than capable as the people 10 years ago, however they certainly have less experience to draw from.
More time in the regional space will give them that.
What’s different is that, they certainly won’t be going into poverty since starting pay now is in $80 range while they are learning, where the people 10 years ago primarily can just say the only benefit was the life experience of poverty and bad credit.

Obviously the airlines will benefit as LCA’s and training center won’t have to teach 121 101. In addition the new cadets may be more appreciative of that IOE trip to Copenhagen more since it surely beats ATL-Spartanburg 3 times a day.