Strangely, his speech now was surprisingly "mild", saying he wants to be a president for all Americans, wants them to "unite and bind the wounds of division"...
Also I think the article you linked is explaining it a lot:
In Clinton he faced a candidate whose unpopularity rating was surpassed only by his own.
Trump copied and recast Ronald Reagan’s promise to make America great again. In four words it captured both pessimism and optimism, both fear and hope. The slogan harks back to a supposed golden age of greatness – the 1950s, perhaps, or the 1980s – and implies that it has been lost but then promises to restore it.
...many Trump voters relished his attacks on the party establishment.