Surely taking a few new pilots of the same level of experience each year means you are getting a spread over time. What's more, that spread is commensurate with age.
And in answer to the PS: I would be happy with pp44 now but not when I have 4000 hrs. If BA really cared about recruiting a broad range of age and experience they would reconsider the archaic seniority based on service and not experience payscale - which operates in no other industry.
However, it s their train set and I would have joined regardless. Just pointing out the obvious, of course.