Starting a business without a solid revenue model is romanticized as 'building first, monetize later,' but I've watched too many founders burn through savings chasing growth that never materialized. My cousin spent two years on a fitness app with zero paying users before pivoting to a B2B model that finally broke even. The lean startup mantra of 'iterate fast' works, but only if you're testing willingness to pay from day one, not just user engagement.