yes. but this amounts to running a `make' over the list of
dependencies at every boot (possibly changing nothing if the dependencies
are up-to-date).

iirc, some developers objected fairly fiercely to that idea (not using
make, but the idea of depending on the dependency-checker, crashes
halfway through the `atomic' dependency-file update, etc, etc.).

Would it be a useful first step to take the existing monolithic
/etc/rc, and break that up into sensible `modules'?
While leaving  all the rc.conf machinery alone?