This isn't a "will be" - this is an *is for the Federal government (whom I work with) and those who take Federal money.Been using iMessage just fine on my Android phones for the last 8 months via BlueBubbles.
Aside from security risks, it's also largely a financial concern that would affect the other suppliers. Same thing with EV cars made in China. If allowed in the U.S., they would obliterate Tesla. If Oppo, Xiaomi, Huawei all had a presence in the U.S., Apple / Google / Samsung profits would plummet. Don't fool yourself into believing that the U.S. and other companies are purely focused on "security."
The issue is finding devices - and I now have a way via CAASM / CPS.
We're pulling out devices left and right, and greylisting/blacklisting ZTE/Huawei/Hikvision/etc.
But since you know more than me, tell me every IP / FQDN your phone talks to?