Open source is indeed unlikely, but there's a very good chance they'd make it free or inexpensive relative to competitors. Plenty of precedent for that in the video editing tools they've bought and turned first-party.

They might not kill off cross-platform support this time, though. Today's Apple maintains true native (not just "port half of the Mac/iOS userland" native) Android and Windows apps.

I don't consider it -likely- but Apple do have form for "buy a thing to -use- it and who cares if other people use it as well" in FoundationDB.

They pulled the code for 3 years though?