Hi Chokri,
(First of all, of the five speakers I have zero trust or respect (anymore) for the PoV of either Vint Cerf or Andrew Sullivan. Both were actively promoting a commercial form of fragmentation -- trying to destroy the .ORG domain by selling it to venture capital -- using the most UNaccountable, UNtransparent methods possible. They have superb experience, but IMO they have demonstrated that their analyses and perspectives are for sale. So as much as I appreciate their historical contributions, I discount their input here as they have previously advocated complete disregard for the public interest.)
Of the speakers, I'm with Eli and Bill. Who are we kidding? There already is Internet fragmentation, in the form of various site-blocking and censoring mechanisms, to varying degree, around the world. If the will exists, protocols can provide bridges between alternate federated Internets; that could enable future innovations that might provide an alternative to the corporate-driven content cesspool that this Internet has now become. Andrew's assertion that "the alternative to the (current) Internet is no Internet at all" is utter BS that demonstrates both self-service and lack of imagination.
(One real-world example of how what was once a single point of Internet failure can be fixed through a federation is the current transition by many from Twitter to Mastodon.)
In the envisioned world of multiple federated Internets, ICANN oversees just a tiny part -- one function of one Internet implementation -- and that's fine with me. I maintain that what ICANN calls "multistakeholdferism" is just a smokescreen over industry capture, and I welcome Internet alternatives offering governance models that have end users and the public interest as core to policy-making rather than just advisory committees on the periphery.