You are ignoring the critical factors:
1. The fall campaign has not yet started.
2. We already know how quickly Donald Trump can take down someone who starts with a very material edge. Have you forgotten what happened to the steamroller for Jeb Bush—considered the overwhelming odds on favorite, last June;— when Donald Trump went after him? (And Jeb never had a fraction of the negatives that Hillary Clinton has.)
You are ignoring critical factors.
Once Donald Trump secures the GOP nomination, it will be a whole new ballgame. The media (except Trump’s pom pom cheerleaders on Faux News) are going turn on him and unleash even more sordid and tawdry news on him. The media will cover up and protect the Clintons like they always do. The media has being withholding fire right now because the WANT Trump to WIN the GOP nomination. But they will be solidly behind the Democrats in the general election as they always are.
Trump could get away with sliming his fellow Republicans, belittling them and insulting them with his silly little nicknames, and snide comments and gratuitous insults. But none of this will work against the Dems in the Fall election.