Comment by gpvos

The .io TLD will disappear, but given its huge use I expect ICANN to allow an especially long transition period.

Since it's two letters long, it cannot be retained as a generic TLD, as it's in the country TLD namespace and might be reused as such for a different country in the (very far) future. With only 26*26 = 676 possibilities and currently around 200 countries you just can't keep old codes around without an extremely good reason.