This was never a "negotiation". It's pretty clear from the beginning that both Epic and Apple were writing their emails for public consumption, not to each other. Epic knew Apple wouldn't give in, and Epic wanted to sue Apple from the beginning.
They might as well have made it "Subject: Antitrust"
That email would have been a pretty rude opening for someone looking for a sweetheart special deal. Not "nice" at all.
Did they intend to write iOS there? That's a pretty big typo in such an important email.
Ah, to be a billionaire running a private company.
I don't know if you've worked in a large company but it's fairly typical guidance that all emails be written assuming that they could be made public.
The guidance I was given was "always assume what you're writing could end up on the front of the New York Times".
That's not what I meant though. I meant that the emails were making arguments specifically targeted at the public and/or the courts. If you viewed the emails as Epic and Apple having a conversation with each other and trying to negotiate or convince the other, they'd be totally ridiculous. Epic made a jerk cold opening, and Apple gave a pointless lecture in response. This wasn't a conversation, it was a debate. The emails were essentially opening arguments in a court case.