On the face of it, Kylie Cosmetics should have been a flop. Kylie Jenner, the youngest of the Kardashian-Jenner clan, launched her eponymous beauty brand in 2015 with a range of lip kits. Since then, she’s moved on to brushes and make-up palettes.

The quality of the products is mediocre. There are no miracle ingredients. And the range isn’t cheap — a 16-piece brush set sells for $360. But in its first 18 months of doing business, Jenner’s brand made $420m in retail sales.

According to a recent Forbes cover story, the 20-year-old is on target to become a billionaire by 2022. That may be media hyperbole — we don’t know much about Jenner’s costs (her products are manufactured by Seed Beauty, a California-based company, and sold via ecommerce platform Shopify), nor whether the revenue rate is sustainable. But the company’s rapid ascent is astonishing in comparison with old-school, pre-social media models of beauty. After all, it took Bobbi Brown a quarter of a century to become a billion-dollar brand. It’s taken Jenner just three years.