Nah, It Doesn´t Really wrote:
As a high school coach (and teacher), it doesn´t take that much time to individualize workouts. (I can usually do it while eating lunch.)
You still have groups. But, using Daniels´ VDOT charts, you still individualize AND group athletes. Everyone with X time trial has Y VDOT and Z splits to hit in their workout. This creates your groups. Your groups could be Top 10 athletes or Top 30. As a coach, you decide.
If you´re using Tinman´s calculator, you still have all these runners within the same time range.
If you´re using Vigil´s charts, again, you have kids in close proximity to each other (i.e. groupings).
Meanwhile, you have all these layers. Slow runners & new runners probably need miles only. Another group is behind & still doing informal workouts, such as fartleks & tempo runs & hills. Then, you have your ¨upper level runners¨ who could be on the track doing mile repeats.
Don´t forget too, there are assistant coaches helping out. You´re not with everyone.
Contrary to your idea, coaches outside the school do not know the kids as well, can´t keep track of them in the halls & classrooms, & have trouble recruiting athletes (if needed). I hang-up flyers, talk to our PE teachers, drum-up support in my classes, talk to guidance (about new students), go to the middle school to recruit, etc.
As for their success, a LARGE team is critical & having dedication from both the coaches & runners is needed as well. What happens if you have a large team without a dedicated coach? They´re mainly on their own trying to overcome mediocre coaching. What about a dedicated coach without a large team? It´s tough to hone those limited numbers into a competitive team. (I feel this pain all too much coaching at a small school.) Needless to say, you need BOTH a large team & a dedicated coaching staff to make anything happen.