Actually, @IcedPurple , the book deal was agreed in July 2021, AFTER his Oprah Winfrey Interview in March 2021, not before, So he has not diluted anything.
The deal Harry (and Meghan) made is for 20 million USD for 4 books, not just for one book by Harry. The other books include a rather ponderous sounding title on philanthropy and leadership from both Meghan and Harry, and a cloyingly sweet sounding book from Meghan on wellness. I definitely would not buy either, but here appears to be a market for both.
I work in publishing so can confirm that payments are divided into three:
Payment 1 on on signing the contract.
Payment 2 on delivering a finished manuscript.
Payment 3 on the book's publication.
This is industry standard.
I believe the amount they actually received upfront has been wildly exaggerated. They will have received at most, one third of 20 million, so about 7 million max, to cover all the four books. There is no way that a publisher will give all of the advance before a book has been written. It just doesn't work that way.
If Harry doesn't deliver the manuscript as agreed, he will pay back the one third for the memoir. The advance for other books will not be affected as presumably, he and Meghan will want to deliver on them all.
If they cancel the whole contract, for all the books, then they will have to pay back about 7 million.
Read more on the deal here.
www.vanityfair.com/style/2021/07/prince-harry-meghan-markle-four-book-deal-20-million-random-house-memoirs-leadership-wellness