i do kinda worry about this but I dont think it can be brought down entirely. Maybe one government of a large country could shut it down and it may affect the price but for a world wide internet shut down, that would be scary as hell.
yeah, that is scary but also it is not real. some things are scary like getting hit by a meteor as you are walking down the street but that doesn't make them come true and there is no need to worry about it either.
in case of internet, it will only go down in case a nuclear war happens and all humanity is annihilated!