I agree the probability is low, but it's clearly not 0, nor will it ever be 0. Is it close enough to 0 as to be not worth worrying about? I don't know the ans

I agree the probability is low, but it's clearly not 0, nor will it ever be 0. Is it close enough to 0 as to be not worth worrying about? I don't know the answer to that question but I'd guess it's far enough away from zero that it could definitely be a concern. Especially since we know that upgrades can be quite slow, especially in the consumer space(if they are ever done at all). Another worry, is now every platform uses OpenSSH (Microsoft, Apple and *nix all use OpenSSH). 22-ish years without a major security problem is a great track record though.