Here's some actual figures.
I'm 7700 of about 12000 pilots, 15 years of seniority in 2012:
Was going to be at #3 or #6 (I can't remember because it's water under the bride) in 2030, but mergers + Age 65 + "other" here's an
actual seniority progression, not just something off a website which really can't be validated:
View attachment 19912
It really doesn't make much of a large difference for me until towards 2020, peaks shortly and back down to regular levels of retirements. Of course, that's "for me".
Unless there's some wide body orders coming down the road that add to the fleet (and not simply replace), there's not that meteoric of an effect that is going to accelerate my career progression to crazy, end-of-the-world levels.