On the surface we can "fix the protocol", yes. But when the value proposition was a protocol that has now been shown to be flawed, what is there to fix? Create

On the surface we can "fix the protocol", yes. But when the value proposition was a protocol that has now been shown to be flawed, what is there to fix? Create a new protocol, which does not exhibit the exploited bug, and hope people choose to believe that this was the only bug that is there? In-production protocols can't really be changed. You can only create a new protocol, and hope people switch to that. And if you, the inventor of the protocol, have the power to just "move over" users to the new protocol, it was never really a protocol to begin with, but more like a backend interface (the difference being that the latter can change without changing the client protocol).