It also leaves a very much smaller pool of talent to fill the 'top jobs' ... if indeed the appropriate talent still exists.
I vividly recall the peaks and troughs of our small ATC Branch* over the years, as our wartime aircrew [filling the most senior posts] disappeared, generating a surge of younger senior officers ... who then blocked promotions for a decade or so. Then the redundancy packages of the early 90s saw a flood of exits at senior ranks, leading to a further surge of promotions which, IMO, pulled some less than stellar talent up to the top.
* Used to be 1 x Air Cdre, 4-6 Gp Capt, ~32 Wg Cdr, ~150 Sqn Ldr. It was pretty easy to identify who was going to be promoted next
