If there was no internet, there would be something else - something very close to it. You know, like when the steam engine was invented, there were several inventors from all over the world that had come up with very similar divices. Or when the first flying apparatuses were built, so many people went up in the air for just a few seconds or fell down right away until the first working small plaine was created.
The time was just right for the internet to come up. If it weren't created in the 80s and vastly becoming popular in the second half of the 90s, something else would have taken its place, like for example Usenet - which was originally supposed to be an alternative. We would have some sort of way to send mails, watch movies "online" or surf on "websites".