What occurred was an odd number of scandals involving two or three of the major candidates via the normal parties. In a way, it was designed so that the run-off (between the top two of the primary system) lead to Macron facing Le Pen. So all of the opposition parties that disliked Le Pen...showed up and voted for Macron. It wasn’t that they were voting for him...they were voting against Le Pen.
Then quietly as the dust settled, because of the way that the primary system is built around multiple parties...you could have asked a hundred French folks about Macron, and more than a quarter had no idea who he was or his policy positions.
I do agree...social media played into the whole thing, and the scandals were bigger and more noticeable than what it would have been ten to twenty years ago.