This is not so much a flip but probably the closest thing to a meaningful 'reversal' compared to the other ones in thread so far. Like, they never said they will never have an App store, styluses are still specialized rather than standard input devices, etc. Obviously, companies both change direction and fail to meet various expectations all the time but 'history of flipping the script' seems pretty tenuous to me, so far.

There's a few more I thought of in this vein, of various sizes:

zfs

java (and also ruby, python) as 'first class' Cocoa languages

GC'ed ObjC runtime

[Ancient history but kinda huge!] just about the entire post-System 7 technology stack and roadmap was tossed.

The behind the scenes story there is that Steve Jobs never actually cleared it with anyone when he announced it on stage, but it turns out FaceTime depended on lots of elements that Apple didn't have the rights to and, therefore, couldn't release into the open without the other rights holders' consent.