Unfortunately, Trump's campaign has been built on his celebrity. His larger-than-life, theatrical candidacy was produced by the extensive recognition of his name along with an enormous personality. Many questioned whether or not his celebrity would be enough - whether a man so obsessed with being nothing less than the "top dog" could bounce back from lamentable defeat.
Reagan and Trump both started a campaign by being defeated in Iowa. Reagan regrouped, and rode a wave of popular support all the way to the presidential seat in the White House.
Trump made a point of pushing the Reagan analogy more generally. However, that analogy exposed not only Trump's strengths but also his weaknesses.
Both men started their political careers as Democrats who migrated to Conservatism later in life. Both men projected toughness, certainty, and clear patriotism. Trump's campaign promise even matches that of Reagan. Both mean promised to, "Make America Great Again." Trump, like Reagan, has shown he can appeal to evangelicals despite his questionable past involving religion and divorces. Trump also has an obvious ability to deflect criticism that has proven him as adept as Reagan, although he may be more defiant rather than charming.
Trump's defiance points to a huge difference in the tone of the two candidacies however. Reagan's vision was positive and hopeful. The America Reagan was in control of was intended to offer liberty to the world and be a shining example for countries everywhere. Trump's vision seems to be closed off from other places. His rhetoric often invokes fear as often as it does freedom.
Personally, Reagan avoided the attacks that have marked Trump's campaign. In his first run for the presidential nomination in 1976, Reagan challenged an incumbent Republican president and nearly defeated him. But his challenge was mounted on the grounds of policy. He advocated the "Eleventh Commandment." "Thou shall not speak ill of any fellow Republican." Trump has made it clear that the same concept doesn't apply to him.
Reagan had formerly been the president of the Screen Actors Guild and worked for General Electric as a TV pitchman and after-dinner speaker. He also grabbed headlines in 1964 with a televised speech on behalf of the Republican presidential candidate, Barry Goldwater. Two years later, he was elected the governor of California. He served for two terms and successfully built a Conservative record on welfare reform and regulated other things.
I say all of that to say, Reagan's candidacy was built on more than his celebrity. By contrast, Trump lacks experience as an elected official. He also isn't apart of any organized political movement. This may have enhanced his "outsider" status, which is very attractive to some voters, but not his ground game. He centered a campaign on opportunism and tapped into popular frustration.