Historically, when all others are concentrating on lowering costs, quality wins.
Publishers with a laser focus on improving the reader experience win over those focused on saving pennies per page. There is an appetite for quality enhanced ebooks at a premium (e.g. audio books, companions).
But it’s not necessarily about simply improving the multimedia experience. The best way to improve revenues, stickiness, and loyalty has always been to ask the customer. Customer data is the best indicator of what does and doesn’t work.