Obvious solution, but a very difficult "sell". Virtually every group (race, ethnic, religious, class, etc.) will be up in arms against such a plan. There will be claims that this would be a bad idea from a pure management perspective, because the early phases of this plan will skew the age distribution towards the elders.

And there will be a push for a parallel, difficult discussion about an age "cap". Supporting non productive elders, is bad economics.