not at all related... the skyrocketing price of ebooks is caused by the skyrocketing costs of marketing & promotion that has far, far, far outpaced normal inflation
a book won't be visible on Amazon if you don't invest, some publishers are spending upwards of $1K a day on ads during a launch-- & these are the indies!
god knows what Simon & Schuster spends
& there's no guarantees anymore that a book will be profitable