It's going to be interesting to see what they do. One of the core arguments when claiming the domain industry enjoys a competitive market is that switching costs are bearable and that switching TLDs is an option if registries increase prices too much.

So ICANN has a non-trivial choice to make. Either they maintain the position that switching costs are bearable and let .io disappear, or they admit that TLD switching is impossible and save .io, which will make it hard to argue the threat of (registrants) TLD switching keeps the industry competitive.

Fortunately, ICANN is based in America, where there's no law that markets have to be fair or that you can't lie.