I would wager that the cost of printing is not what is setting the high prices for these books. Short-run publishing is quite economical these days. It's the overhead cost of running these organizations -- sales forces to sell to libraries, editors, proofreaders, marketing folks, etc.

Switching to e-book will save very little of that money.

Sure, it allows for self-publishing, but a self-published Ebook is not going to look great on your CV, and the royalties are not going to matter much if only a few hundred people are interested in the topic.