Protection against a potential weakness in ECDSA has been included since day 1. Don't reuse keys.
It doesn't help,
if someone can crack the key before your tx gets confirmed and has a better access to miners.
Use your imagination, mr bitcoin elite.
Also, in reality, a sudden catastrophic break in ECDSA is pretty much unimaginable. There have been zero sudden breaks of that magnitude in modern cryptosystems.
How is it unimaginable when the trapdoor is based on math we
think is hard? "It hasn't happened before, ergo..." is a logical fallacy. "Modern" cryptography has been primarily based around symmetric crypto which is much simpler and does not rely on trapdoors.
There may be some value to adding this to the system in advance of the need to use it. It may even enable some other useful things. But it would be a fork.
There is
definitely value in additional protection.
Old systems were broken suddenly because they sucked. No one knew they sucked, because no one was looking at them. Anyone can design a system that they can't break. Our systems don't suck any more. They aren't built in the dark. Everyone looks at them. In fact, a decent fraction of the intellectual power of the human race is devoted to examining cryptosystems. The really bad ideas are
gone now.
I understand full well that the history of modern cryptography doesn't absolutely preclude the chance of a sudden break, but it certainly relegates it to the domain of extreme long shots.
If you feel strongly enough that the threat is so great that we need to take action now, feel free to do so. All of the source code is publicly available. Design and implement something. Test it out, prove to the world that it works and is safe. Convince everyone that the risk of changing the system is small enough that it outweighs
their estimate of the risk of a catastrophic break. No one will stop you. Plenty of us will even help you with design and implementation.
Just don't expect to make any friends by telling people that they must do your work for you.
However, I have to agree with hashman that it is essentially the end of any trust in bitcoin as there will be many unprotected addresses, especially a lot of the early coinbase tx that will never be protected by anything added to the protocol later.
Dormant keys are protected by dormancy. Unless in this hypothetical world SHA-256 is broken at the same time as ECDSA.