The Microsoft Word example is not entirely accurate. Most office application are in fact having well defined interfaces through OLE [1]. This works in several languages like Perl, VB, Delphi or Python.
good point.. it's not because the application itself seems monolithic the underlying strcuture is.
Apart from that, how on earth would the author go about teaching an average Joe-that-wants-to-type-a-letter that instead of having to open a single program and start doing everything he can imagine, he now has to use 100 seperate programs each entitled to a certain task?
[1]: http://www.adp-gmbh.ch/perl/word.html