Insane. That's like having a link to iBooks in every Amazon app.
No way this will happen. It breaks the ecosystem. Apple will never permit this.
Apple was found guilty of "facilitating a conspiracy" to fix prices in the ebook market in a federal district court.
They don't have a say in the matter. They chose to go to court rather than settle. They lost. They are now bound to whatever resolution the court deems to be acceptable (pending appeal, of course).
Your analogy is completely foolish and wrong, by the way. This is the equivalent of Apple launching an Android app for iBooks, and Amazon then forcing Apple to give Amazon a 30% cut of every iBooks sale on the Android iBooks app, and requiring anyone else who sells iBooks (like Apple themselves) to offer the same high price on every product, and then Amazon conspiring with all of the book publishers to raise prices and force that model onto Apple's store, and then sitting on that business model in bad faith for 2 years until forced by a court to relent and allow Apple to sell ebooks via their iBooks Android app for whatever price they want, and from within the app, and without paying Amazon 30% of every sale. That's the analogy you were looking for. And it shows just how absurdly defensive Apple apologists can be.
Amazon is "winning" right now because they have built up such an incredible infrastructure for real, physical books (and practically everything else) that people go to them like they go to wal-mart. Wal-mart has terrible prices sometimes for certain things (like cheese or milk, for example), but the people who shop there don't know that, because they don't shop anywhere else. Amazon has a lot going for it

rime shipping (no competition), Prime video (better than netflix in a lot of ways), subscribe & save (no real competition), the Kindle (best ereader family), S3 services (best price/performance in the industry), the Marketplace (taking a huge bite out of ebay, et al). What they aren't doing is using anticompetitive practices to actively hinder the business efforts of their rivals in those markets. Apple and the publishers were doing exactly that.
If the walled garden philosophy works, then Apple's iBooks store should be able to compete with the Kindle store on iOS without stacking the deck. If you want to pay a 30% commission to Apple for every purchase, then that's your right. It's not Apple's right to dictate pricing for other companies on their own website, which is what the current policy effectively does.