If well documented manipulation of social media by foreign governments had a "minuscule" effect on the election, what are the "far more probable explanations" you speak of?
Hillary didn't take any non-screened questions from the press for a period of several months during the heat of the campaign.
HRC campaign was overconfident in swing states and chose not to campaign there.
If advertising can win elections, then Hillary would have won since she far outspent Trump on media. Let's not forget she had a much larger army of astro turfers (Correct The Record) pushing her message on the internet and it was all for moot. It turns out people aren't as easy to sway as advertisers would have you believe.