02. He won because of uncontrolled social media hype particularly Facebook. This was really evident because of Facebook and its inability or unwillingness to crack down on fake news which spread like wild fire on its platform. Other social media networks became a clearinghouse for fake and sensational news. These were not just simple partisan spins, but outright lies peddled as objective truths by shady and obscure actors both inside the US and abroad. That helped Trump quite immensely.
08. He won because Democrats focused more on turning out supporters than growing the base. The Democratic Party campaigned as if it had left or given up/abandoned/lost touch with the working class, its traditional support base. They focused more in a lame effort to persuade people outside their base while ceding everything else to the Republicans. That miscalculation helped Mr. Trump to win.