That depends upon what you mean by ‘the Internet’.
I was taught at Harvard that the whole thing works because of the protocols that allow one computer to ‘talk’ to another. And because of ‘packet-switching’ – the way digital information is broken up into tiny scraps that then each make their own way around the world’s telephone systems to re-assemble in an instant to let you read this webpage.
Then there’s the domain-name hierarchy – not much use having a message system without a standard address system.
Some of this is down to the priorities of the then US governments – most of it is down to private initiative and leaps of personal inventiveness, coupled with the ability of companies to grasp the potential of new ideas. Or not.
Read this on the background, including on how Xerox did not know what they had and let a young man called Steve Jobs share their knowledge…