Every single ones of those techniques can and would be bypassed (the app store banning would be the easiest). The ISPs would be operating on an "anti-virus" principle, and they'd be too slow to stop "zero-day-like" hiding of encrypted communications before an attack would happen. There are already plenty of apps that stop carriers from knowing when someone is using tethering apps, when the carriers don't want them to use those types of apps.

As someone was saying on Twitter, intelligence agencies should not want terrorists to start using steganography...which would make their passive traffic analysis much harder. But if they start censoring and banning encryption apps (which use metadata all in the clear), that's exactly what will happen.

Also, it seems most people live with the impression that "if only current apps such as Signal, Tor, etc" would be banned, that should pretty much put an end to encrypted, hidden communications, right? Wrong. Dead wrong. Right now they are being "lazy" and just use what's available to them, like Telegram and whatnot. But if those apps were actively banned, they would focus on building their own, perhaps with forked Signal/Telegram sources. But even without those, they could still commit to building their own solutions.

To give you an analogy, look what's happening with the Silk Road-like world. Authorities stopped Silk Road - like twice or third times already. But the underground online drug market is bigger than ever - it just split into multiple smaller markets. If that happened with drug businesses and drug delivery, it should be much easier to happen with "chat apps".

People would still want strongly encrypted apps especially if they were actively banned by oppressive governments.