What could Apache possibly lose?
"Its a bluff and if they actually do it, then the only ones to lose is Apache."
What could they possibly lose? The only things they get from being in there is a say in the decisions related to Java roadmaps, and a way to get licenses easily. Now Oracle has made abundantly clear that they won't listen anymore, and they refuse to grant licenses, ergo Apache doesn't benefits from being in there. On the other hand, having Apache in meant a lot for the open-sourcers and largely contributed to the success of the language. If Apache leaves, that's largely gone. Also it's bad for the image of the language, which future appears fragile (and which looks more like a lock-in).
If anyone loses, it's certainly not going to be Apache, simply because staying would not bring them anything to begin with.
"Suppose Apache walks away. Oh no! What will Oracle do? Hint: They'll pick up the code, and maintain their own in house release."
Even if they did (which they probably won't as they clearly have no interest in it) that would cost them money. Unless they found a way to make developers work for free.
"game theory"
Game theory doesn't explain how working for free for Oracle and giving them support when they fail to uphold their end of the deal (trying to publicly humiliate you in the process) is a good idea. Can you spell it for me, again?
Would YOU do free work for Oracle knowing that you'll be denied the right to use the tool you built?