The reality is that you can coach many riders at once if that means an hour a week of going through power meter files and training plans. But really teaching tactics takes riding with clients, attending races, riding or driving a support car in races and more. In other words a much larger time commitment. That is why many new riders learn more tactics from experienced team mates that are actually in the same races and group rides as them then they can learn through a coach. I don't think coaches are hiding secrets or at least not writing them down to keep a competitive edge. I just think it is tough to teach without direct involvement.

Still, I think a well written, entertaining book on race tactics would be welcome by a lot of riders.