I doubt someone could ‘turn off’ the internet, even if one or many companies gave someone the ability to do so. It would be like trying to give someone a “kill switch” over all of the electricity in America...
Sure many would lose power, but others would continue.
The internet is far too dispersed, with much of it outside of our borders and jurisdiction to have any hope of controlling it.
>I doubt someone could ‘turn off’ the internet,
The most vulnerable point are the root DNS servers. You turn those off and bad things happen.