Uh, no. You're paying for middlemen (printing, marketing, big publishing, etc) . Authors typically take 10 to 15%, either of royalties or net profit.

I've never paid for a printed ebook.

Well no shit. You were arguing that the significant portion of the cost of physical books is the writing. It's not.

No, I was arguing that one should not expect ebooks should not be massively cheaper than paper books just because they aren't printed. There's still a lot to pay for.