Facetime faced a patent lawsuit, and Apple had to change how it operated (to have it relay through its serves), making not that great as a direct communication standard.
That was a last-minute uninformed decision about a completely new product. Swift's open sourcing is clearly planned ahead of time and has actual the full backing of the company.
Apple also said they would make FaceTime an open and interoperable protocol "later this year". So being sceptical of Apple's promises of openness are justified.
The fact still remains that Apple made a big promise without analyzing all the legal aspects of it. Most average to big size companies do the reverse of it - Make sure the legalities are in their favor before making big announcements.
Are mistakes not possible in your world? Somehow I doubt even an exhaustive legal analysis would have turned up a patent troll. (Kind of characteristic of patent trolls, really)
It's hard to know what really happened, but the story is that it was basically Steve Jobs who made that big promise himself. It is said (and again, who knows if this is true, but that's the story) that the first time the FaceTime engineers heard about making it an open standard was when Steve announced it to the world.
Open sourcing Swift, on the other hand, is clearly something they've been planning for a while with the full knowledge of all involved and wasn't just a sudden impulsive sort of thing.
Apple's Dylan language is now open source.[1] It's abandonware, but it's open source. (Jobs: "It's dead. We killed it.") The obsolete Macintosh Programmer's Workbench is also open source now. When Apple open sources something, it's usually because they're abandoning it.
Open source Dylan was open sourced by a company called Functional Objects. The Macintosh Programmer's Workbench was never open source to my knowledge.
Since both of these are semi-obscure and incorrect it's obvious that you've just cursory searched for stuff you don't have direct knowledge of just to bass Apple (which has open sourced several things as well as provided changes back to the community, and not just when the license forced its hand).
MPW used to be available from "ftp://ftp.apple.com/developer/Tool_Chest/Core_Mac_OS_Tools/MPW_etc./", but Apple took their FTP server down. There's still a mirror.[1] It's mostly ".hqx" files, so you need to find something that can decompress old Stuffit files.
Is there even one doubt that this will happen?
If not, the pedantic distinction between "announce they intend to" and "doing it" is extremely worthless...