Well, at least at currently, the "US Internet" includes IANA, Google, Amazon, Netflix, Facebook, Verisign and a majority of the root DNS servers...
Changes made to the "US Internet" are going to absolutely affect the wider world right now.
Changes made to the "US Internet" are going to absolutely affect the wider world right now.
As for those companies, they'll work the same way as before outside the US internet. Regrettably, because the world would be a better place without them.
This change doesn't directly affect IANA, etc, but it will likely have knock-on effects which hurt everyone.
"IANA can be replaced by a non-US entity" - This would, IMO, signal the end of the internet. "Look up www.google.com" "which one?"
I'm not entirely sure if you know how DNS works.