I cannot see .io domains going away despite all the evidence to the contrary.
- Yes, ICANN has a policy that retires TLDs when this happens
- Yes, ICANN has retired multiple TLDs in the past
Google and Microsoft both use .io domains and have close ties to ICANN. I think they will be able to broker some sort of deal.
That being said, the whole problem is uncertainty.
Buying a domain is a very important purchase. Even if you change domains down the line, you need to keep your old domain for your old links to work.
It is for this reason that I do not understand ICANN's ccTLD retirement policy.
In a utopian world where our goal as humanity is to reduce the amount of link rot on the web, retiring TLDs make no sense.
Regardless, I would like to see an official verdict on .io domains soon. The longer uncertainty lasts, the worse things will get.