In the same way I don't trust Google not to cancel whatever it is they just announced, I don't trust apple to keep supporting software on platforms that aren't theirs. They just don't have a good track record and no real incentives. The last widespread Apple sosftware on non-Apple platforms was probably iTunes, which was terrible.
To be fair it was terrible on macOS as well.
I do trust Google not to cancel one of their core (or most popular) products, like search, Maps, Docs, Android, etc. Anything else I don't. I do use Google Photos, but I wouldn't be too surprised to see them shut it down one day.
Apple's recent track record (Apple Music, Apple TV) is surprisingly good. The apps on Windows and Xbox have been trending better/gaining features at a good pace with respect to Mac OS and iOS.
There is a sense that Swift has opened up cross-platform app initiatives at Apple that they wouldn't have done just a few years back.