They wouldn't need to stop using Apple products, they would just use encryption on top of it. Even if the iPhone is 100% unsecure, all that means is that there is nothing blocking access to the contents. The contents can still be encrypted, there are dozens of encrypted communication apps out there already.
So they should be able to do this without effecting quality due to better compression algorithms being available now, but what problem is this trying to address? Other then keeping that one intern they don't like locked in a small room running HandBreak 24/7.
Every time there is a mass-shooting or similar, gun sales go up because the marketing department of the gun manufacturing lobby (NRA) goes into full swing about how the gubement is gona take yer guns. So this is perfectly timed to capitalize on the latest shooting.
Current iteration as far as I am aware does not run apps natively, it is just a front end for your phone. In a generation or two of the API (hardware does not need to be updated) this will be addressed and we'll see.