Most SaaS founders spend 3 months building a marketing plan. 45-page deck. Competitive analysis. Market sizing. TAM/SAM/SOM calculations. Buyer personas with stock photos and fictional names like "Marketing Mary" and "Sales Steve." Then they launch. And reality hits. Half the assumptions were wrong. The market doesn't behave like the spreadsheet predicted. The carefully crafted personas don't match actual buyers. The result: Wasted 3 months planning. Now 3 months behind comp