They already operate in China, allowing the Chinese government to access all "Chinese" user data. Non-Chinese Apple accounts also work perfectly well in China, which leads me to believe that the extent of data sharing is greater than has been disclosed (or dissidents could just use a foreign phone to avoid surveillance). I strongly suspect the CIA/FBI/DHS has similar access.
(Microsoft stuff also works fine in China, Google stuff does not. Draw your own conclusions.)
I think it's somewhat likely they'll just backdoor it and not tell the public, they can see this is just the way the world is headed.
If you want to message someone secretly, use an audited open source solution - don't rely on a megacorp to look out for your interests.