I agree completely with the sentiment.
However, because LilyPond changes so frequently, it would have to be almost like a subscription with loose-leaf pages in a binder, so that when something changes, we could print out replacement pages.
I haven't thought through this, but maybe something like: Say that Chapter 1 includes pages 1-1 through 1-40 and when an update occurred we could replace pages 1-3 through 1-8 with pages 1-3a through 1-8d (and then the next page would still be page 1-9 etc).
Larry Kent
Tampa FL