I think there's some good perspective here: Pearson's "Free" LMS
I could see undergraduate publishers moving increasingly towards "entire packages". Not just the text, but instructional videos, forums, online workbooks, etc. Instead of buying a textbook, you buy a course. That raises a lot of questions about "where's the prof in all of this." I see that problem now in what a lot of publishers want to sell our department for the undergraduate teaching I do at another school.
We're just not that big a market for Publishers. Many of our texts are obscure, useless to the larger market, and not easy to design a "complete package" around. Theological Education will probably remain on the outskirts as Publishers jockey for position in the more competitive segments of the Ed market.