@rysiek IANA has made a specific policy about this because they don't want a repeat of .su or .yu. Most TLDs for countries removed from ISO3166 have been deleted from the root zone, e.g. .tp, .yu, .zr, and .an.

Under the policy retirement would take up to 5 years after ISO 3166/MA takes action, or 10 years if the registrar requests an extension.