[Boudica]

At the point that our technology is at right now, the only thing that could bring the internet to a halt, would be an apocalypse. The internet isn't one entity, it's a collection of billions of servers, websites, images, and plaintext. Servers may go down on occasion, but if they are consistently monitored, they'll be back up within hours. I find the idea of the entire internet going down, very unlikely.

Exactly this!

Think about road networks. We could say, as there are more and more people on earth, won't all of our road networks collapse? Well, that hasn't happened. It's not one singular entity as said above. It's made up of lots of different segments, which are improved, built up and expanding all the time. Roads didn't disappear, they got re-laid and made larger. The same will happen with the cables and data centres that make up the internet.