As far as I can find .su is the exception in surviving, not the rule, and who operated the ccTLD is irrelevant to the question of whether ICANN decides to allow it to live on.
It does seem likely that ICANN won't kill off all existing registrations, but this is supposition, not an answer. If we look only at what they've done historically to ccTLDs the most likely outcome is that new registrations become locked and ICANN attempts to phase the .io TLD out.
They may break that trend now given how much they've already polluted the TLD space, but they may not, and I think your comment is a bit too optimistic. People with .io domains should absolutely be paying close attention here.
Edit: gnfargbl found the actual written policy [0].
It does seem likely that ICANN won't kill off all existing registrations, but this is supposition, not an answer. If we look only at what they've done historically to ccTLDs the most likely outcome is that new registrations become locked and ICANN attempts to phase the .io TLD out.
They may break that trend now given how much they've already polluted the TLD space, but they may not, and I think your comment is a bit too optimistic. People with .io domains should absolutely be paying close attention here.
Edit: gnfargbl found the actual written policy [0].
[0] https://news.ycombinator.com/item?id=41730559