This is a perfect case against centralized messaging: no company = no liability.
Sorry, moxie; there's going to be no way to have a beautiful e2e encrypted IM еxperience under wise oversight of a single company; only ugly p2p hodgepodge without a legal SPOF has a chance to pull it off.
We still need to replace the ultimate centralized industry: internet service providers. The telecommunications industry has always cooperated with the government and they can be ordered to block the "dangerous" messaging services. We need to somehow replace ISPs with a world-wide mesh network that can't be censored no matter how much governments want to.
I agree that ISPs are a problem, but it's possible to build a reasonably blockproof service with a doze of p2p darknet and reliance on common transport protocol (read: https). They would, essentially, have to find every node on the network and block them. Or perform very expensive traffic analysis, which can be defended against by designing normal protocol traffic to look very much like normal web traffic.
As always, adoption is going to be poor because even among geeks it's rare for one to deeply care about privacy & anonymity let alone lift a pinky for it.
Unfortunately, the worst threat is a legal one: just offer punishment for anyone who is found guilty of participating in such a network.
Unlike Signal, however, which the parent was taking a pop at - ISPs federate. This is a decent insurance policy in places covered by more than 1 ISP - if an ISP starts blocking content people want, they'll lose their customers overnight.
Not so good in most parts of America, though, where there's often an ISP monopoly.
It doesn't have to be p2p. It just needs to be sufficiently decentralized, like email. If a company provides software but not a service then it's not liable under the new ruling. You can also run it outside of US jurisdiction. For example, use something like https://github.com/tinode/chat to set your own chat service.
Sure, they may try to go after a myriad of individual operators but it's a completely different story that forcing half a dozen US companies to drop e2e encryption.
Sorry, moxie; there's going to be no way to have a beautiful e2e encrypted IM еxperience under wise oversight of a single company; only ugly p2p hodgepodge without a legal SPOF has a chance to pull it off.