You don’t need a political party to get on the ballot as a candidate for public office. Just ask someone like Willie Norwood of Atlantic City, who is a losing candidate for some public office every year.
You don’t need a McDonald’s or Wendy’s franchise to open up a hamburger restaurant. But if you want to sell hamburgers to, or get votes from, thousands of people who know nothing about you, you need a well-known brand name, expensive advertising and a team of experienced and trained marketing professionals. It takes years of hard work and lots of money to build these things from scratch. But you get them instantly from an established franchise.