DRM means missed opportunities for e-books

This is actually talking about missed opportunities for publishers, not ebooks per se. Despite all the talk about author support/development, curation, editorial services, and the like, publishers have historically maintained their cartel-like position for one reason alone: the amount of capital required to go into the publishing business. They've profited immensely by wedging themselves in between the money and the talent, and for obvious reasons they don't want that to change. In point of fact, publishers have been low-balling their author services for some decades now. Unless you have the sales clout of a Stephen King, you are going to see precious little publisher support, and may well find yourself dropped even if your books are selling (just not at best-seller levels).

Unfortunately for the publishers, the amount of capital required to go into the publishing business is now effectively zero.

Yes, an author might still want to hire an editor, a cover artist, and all the rest, but the key term there is "hire". There's no longer any reason to fork over 85% of the profit from your book to some middleman, and more and more authors are wising up to this fact. Publishers do provide advances to authors, but you'd likely be better off in financial terms by getting a bank loan, or heck, even a credit card or payday loan. Yes, you will have to pay interest, but at least those organizations won't claim to own 85% of your book's profit in (effective) perpetuity.

Amazon, Barnes & Noble, and the rest will put your ebook in their store right alongside the most recent offerings from the Big Six, and you will likely make more money from pricing your book at $2.99 (or even $0.99) than you will from your share of the the DRM-encrusted $9.99-$19.99 book from the major publisher.