Why 90% of great products fail at customer discovery

I've been analyzing failed product launches for the past year, and there's a pattern that keeps repeating that nobody talks about. It's not that founders don't do customer discovery - most actually do. They survey people, run user interviews, even build MVPs based on feedback. The problem is they're discovering customers in the wrong places. Here's what I mean: a founder builds a project management tool. They survey people in general startup communities and get positive feedback. They launch and... crickets. Why? Because the people who really need project management tools aren't hanging out in generic startup forums - they're in specific communities complaining about their current workflows. The actual customers are in places like:

Niche subreddits for specific industries Discord servers for freelancers in particular fields LinkedIn groups focused on operational challenges Slack communities for remote teams

Most founders never find these communities because they're not obvious. They're buried 3-4 clicks deep from the surface-level places everyone knows about. I realized this after three of my own products failed despite "validating" them with hundreds of people. The validation was real, but I was validating with the wrong audience segment. The breakthrough came when I started treating customer discovery like investigative journalism instead of market research. Instead of asking "who might want this?" I started asking "where are people already complaining about this exact problem?" This shift changed everything. Found customers who were not just interested, but actively seeking solutions and willing to pay immediately. Has anyone else noticed this pattern? How do you find the communities where your actual customers spend time?