I think people need to be realistic - none of those are particularly ground breaking ideas, as evidenced by the fact that there are countless competitors and in many cases even predecessors that were not in the right place at the right time. These people just happened to be born to the right parents in the right country at the right time to have the privilege to have someone throw money at a not very original idea that could have been anyone's. Great for them, but I think it is worth staying grounded and realise that they're not visionaries and had they not even been born, someone would have thought up the same idea anyway. Monkies and typewriters and all that.
So maybe we'd not have "Reddit", but we'd no doubt have something largely identical that would fill that same niche. Equating any of these trivial things with something like the transistor is just absolute arrogance.
</unpopular-opinion>