False. Without internet there would be a Linux.
Interesting way to put it. If there is a Unix, then there would be a Linux. Would there be a unix? OK, yes, there would be networking without "inter-networking". So there would be a Unix and hence a Linux.
There was telephone, there was AT&T, there was Bell Labs, there was Unix. Looking back it seems inevitable. Similarly, once there was networking, there would be long distance networking.
A society based on central control and information secrecy would have not developed an internet, but even the red scare of the 1950s did not bring the United States to that extreme.
Interesting question. Interesting way to ask it.