Up until The Apprentice, Trump was widely considered a clown. For example, in the '80s and '90s, NYC-based Spy Magazine made fun of him regularly: https://www.boweryboyshistory.com/2015/08/spy-vs-trump-the-b...

As with many notable people today (e.g. Kim Kardashian), reality TV drastically elevated his profile and gave him an enduring fan base.