Realistically I don't see how it would ever not be managed by a corporation. Your average person doesn't know how and doesn't want to manage their own messaging system. They are just going to offload that responsibility to a corporation to do it for them. We are just going to have exactly the same system we have now. Just called some else besides email.
I wish there was a better solution but I am not seeing a way that doesn't just end up the same as email.
Yeah that is a fair point.
I have never been involved in anything like that, so I don't know how big of a risk that actually is for most people.
And I would think as we get more and more cloud dependent any data on the phone would also be stored in company servers. So I am not sure the value a subpoenas for phones would be.
If it gets that far I would wonder if there could be a case for them of taking both personal and work phones as well just to be sure no one was talking outside of the company's standards communications.
Again I Have no idea how legally that would all go down, but I do think you being up a very good point the more speration you have between personal and work the less grounds legal action has to stand on to enter into your personal devices.