Sorry that I am not all the way through the posts, yet, but I don’t believe that the posts #246-#255 really responded to the comments that TheGFG made in #245. Perhaps that is coming up.
Our area has the same intensity of all of the EC’s that were typical a generation ago: e.g., sports, music, debate, or volunteering. In swimming and water polo, two-a-day practices are common, with the first starting about 6:30 and the second after school, plus travel to events, plus team fund-raising, plus . . . The future looks worse: A relative of mine has started his two-year-old on swim lessons. The two-year-old’s grandfather still swims competitively at a national level, and wins in his age group. The two-year-old’s mother was featured in Sports Illustrated–just a Face in the Crowd, but still. The two-year-old is not the only swimmer of his age group.
At our high school, a teacher started a new team sport (really a pre-existing sport, just one that was not played in the area before), which offered students who did not have the U4-type of experience an opportunity to play something. But one can’t exactly count on that, plus the sports would keep getting more exotic, requiring more travel time, and more team fund-raising.
I already mentioned QMP as 17th or so cello, vs. my spouse as the whole cello section in his high school orchestra–and his was and is still a good school.
On other threads, I’ve mentioned my high-school debate experience vs. the current day. My high-school debate team met once a week for an hour after school, and traveled only on Saturdays, except for the state tournament when we made that (which was just once, as I recall). I read a little on the topic to supplement the pre-printed evidence cards that we were actually just handed. We could fit them in a small file box. One of our JV debaters carried a single “evidence” card, that actually just said “Smile.” Fast-forward to the present: The debate team meets for multiple hours a week. They frequently leave for tournaments Thursday nights, and the tournaments run multiple days. Instead of a file box, they have a filing cabinet on wheels full of evidence.
I volunteered for the Red Cross as a 14 year-old. Can’t do that anymore–must be at least 16. I volunteered as a Teacher’s Aide for Head Start. Probably can’t do that at all in high school anymore, in our area. Those are among the most-coveted volunteer slots for the college students.
I don’t know what the process for starting a new volunteer club at the local school is/was. I don’t believe it was restrictive. But most of the logical topics were already covered. I know: Pie Club hasn’t been set up! 
If the EC your child really, really wants requires a group, and the groups is intense . . .
What I would like to see is more activity offered at the MIT softball “Kentucky-Fried” level. Perhaps in retirement, I could volunteer to start such a club locally, as long as I don’t mind being finger-printed and regarded with extreme suspicion, if I can do it at all. (At the local school, parent volunteers cannot run any activity that the teachers can be paid to run.)