Startups fail for many, many reasons. This is just what happens. Paul Graham famously observed that most die from suicide, not from homicide, meaning that it is not the competition that kills, but typically the founders themselves destroy the business. Founders can break up or execute poorly. More often than not, founders can’t build the product that’s good enough for the customers to buy. If the founders are technical but not commercial, they may build a product but struggle to sell it.