Let me put it another way: the [20, 25) and [25, 30) age cohorts are larger than any cohort aged 50+ that might have recently aged out. So that "prime age" workforce is still growing.
This could be true, but it isn't obviously true (to me). (I dispute a little bit the idea that there are many new workers in the [25, 30) demo.) There are 37M workers 55+, but only 20M in the 16-24 range: https://www.bls.gov/cps/cpsaat18b.htm (2024 numbers)
Nobody in either of those cohorts is in the BLS "prime age" group which is [25, 55). The incoming cohorts that are now 15 to 25 are larger than the outgoing cohorts that are 45 to 55.
