ARPANET was not the only network in existence, even then. Networks existed in various forms. Later, BBSes existed. My guess is sooner or later there would have been something (probably more than one, even) our current internet, but we would never know. Would it look worse or balkanized or proprietary, my guess would be yes, I give you that, but we'll never know that either.
(I originally noted in my topmost post minimal, surgical, involvement is the aspiration, not necessarily zero, but I digress.)
