Casper didn't just sell mattresses — it sold the idea that a 400-year-old industry was broken and only a Silicon Valley startup could fix it. Investors believed them to the tune of $339 million, right up until the moment the IPO numbers revealed a company spending $300 to acquire a customer who would never buy a mattress again. This week, we unpack how a genuinely clever direct-to-consumer idea got buried under venture capital ambition, a category that doesn't scale, and the oldest trap in consumer retail.