Demographically, the middle-aged, as implied by the appellation, form the middle part of the populace, both in terms of age, and, owing to the especially prolific habits of their immediate forbears in the decades following World War 2, their absolute number.
That is to say, using the size of our cohort as the metric, we form the meaty part of the bell curve. This is changing, of course. Like a fat mongoose being pushed peristaltically through a snake, the lump is moving steadily towards the long tail, and then…well, towards the infinite.
Of course, no no likes to consider the infinite. The ancient Greeks avoiding accepting the infinite (and its fraternal twin, the number zero) as part of their number system because it represented the void, and who likes to contemplate that? I certainly don’t, nor do most of my middle-aged friends, which is why they (like the Greeks before them) go to such lengths to pretend that it doesn’t exist.
But we’re all on the same glide path (to borrow an overworked business metaphor — then again, to call a business metaphor overworked is in itself a redundancy, isn’t it?), and consider it we must. With any luck, we can make sure the glide path isn’t too steep, and our final descent not premature.