So what's the answer? :)
A few thoughts on the matter:
Weren't telephones around the world linked up privately? If they were subsidized, how much?
Also a global internet is going to be more profitable than closed networks, wasn't AOL a closed network at one point? And I think I've heard of other ones that completely failed.
To be quite frank, I really don't care about mind games about how stuff might have happened, or how stuff might happen in an alternate universe :D Especially if something like the internet is a logical conclusion of having computers that connect to each other.
(Btw, when people say big-L Libertarians, they 99% of the time mean people from the Libertarian party. Though, I have seen even people like Jesse Ventura think that means anarcho-libertarian, or anarcho-captalist.)
So yea yea you won't take me seriously (which accounts for the tone of my comment) but no one can prove either way if the internet would exist if there just so happened to be some libertarian society so I would advocate voluntarism rather than coercion (anyone can test out for themselves if something is coercive or not, e.g. trying to not pay taxes).