Guessing here, but I suspect the % of people at 65 that can pass 1st class medicals for 2 more years is much lower than the % of people who could pass 1st class medicals at age 60 until 65.

I suspect we left a lot of reasonably healthy talent on the ramp when they hit age 60, there won't be as much at 65.

It's just not the sky is falling situation as some will make it out to be.