I don't think that a modification API helps with anything.
ok, i guess you don't need an operating system then. just flash software to your ROM directly. since, an OS is literally a modification API for computers.
I know that the work itself never addresses that
and therefore, is not a valid counterpoint. if it's so trivial to derive, then provide a point-by-point breakdown of your trivial derivation.
I think that forks rarely become many because most attempts to fork a project will invariably get absorbed into the main project or one of the few forks that fills a unique niche different from the original project.
and also a plugin API. that's a very important reason that cannot be overlooked.