

Because they are fucking old. Old clocks. Useless clocks. Not a skill worth teaching, except as an anachronism when explaining why Big Ben and similar building clocks work the way they do.
it appears children have fallen out of practice doing so in an increasingly digital world.
Increasingly? Brother, we’re already there. It’s all digital. Have you seen the internet yet?
Schools haven’t adapted solely out of spite, to propagate this self-fulfilling cycle of teaching how they work, so that their own students can read school clocks. As soon as they leave the school zone, that knowledge is practically useless to them.
Nope, not really. You occasionally find them in some old government building, but only because it’s always existed that way, and they just don’t want to bother replacing it with a modern digital clock.
This line of thinking is the same as saying cursive writing is worth teaching.