Perceived leverage. HC would have been able to operate with greater flexibility without the deal and Amazon now has dominant market share. Jobs argues that Apple's digital subscribers are the important part of this deal when a very legitimate argument could be made (especially in retrospect) that Amazon's ownership of the book market, and book commerce traffic could help it's marketshare even more.
The lesson is to convince someone reading the negotiation that you have all the leverage, and Job's certainly seems to have done that. So much so that you dismiss any lesson as all.
You didn't explain how HC had the leverage in this negotiation. Apple had already closed deals with a number of publishers. They were go for launch and it was inevitable that the overall market was going to ultimately decide if iBooks was a winner, not if HC's content was on board or not. If iBooks tanked after launch, it would almost certainly not have been due to HC not being on board, and if iBooks was successful, or at least was getting traction, HC would be groveling at Jobs's knees to participate with the stated terms, if not better ones. Essentially, Jobs saw HC's participation as a net positive for Apple, but only if they participated without altering any of Apple's terms. This mindset is exactly why Apple had the leverage: they could comfortably walk away, while HC saw themselves as potentially missing getting in on the ground floor of something that could kill their business if they weren't.
The lesson is to convince someone reading the negotiation that you have all the leverage, and Job's certainly seems to have done that. So much so that you dismiss any lesson as all.