The difficult comparison here is that we have never seen any company monopolize so much of media as we have facebook and google do world wide. The only comparable example I see is possibly disney, and I wouldn't be surprised to see facebook and google succeeding far into the future due to well targeted acquisitions.
Additionally, it's important to remember that all of the largest american oil companies today are descendants of standard oil, and I imagine such could very well be likely if any of these other big monopolies were broken up today when it comes to the internet.
The point is that when declaring "this time it's different", you have to explain away all the many, many things that are exactly the same, and not just point out the one thing that's a little different.
The Facebook/CA scandal broke in traditional media, and traditional media hasn't exactly been downplaying the possibility of Facebook-powered "fake news" influencing of elections, either. I think that tells you everything you need to know about the purported monopolisation of the media by Facebook.
Additionally, it's important to remember that all of the largest american oil companies today are descendants of standard oil, and I imagine such could very well be likely if any of these other big monopolies were broken up today when it comes to the internet.