Being an influencer is the new big thin to get rich in this era. It is not about being a celebrity, but to be someone who can influence the people that looks up to you. Your fan base is your network, they are the people who can sell your business to everyone without you breaking the bank for Ads. Like the example you gave, Kim Kardashian is a highly endowed figure to women, most young females want to be just like her, most men simp on her too, while other genuinely like her personality. So yeah, she will definitely sell out on her first day.