Founders must consider their sales motion (e.g., PLG vs. enterprise sales-led) when designing the product. A product built for one motion won't sell effectively in another, potentially forcing a costly redesign. This concept extends "product-market fit" to "product-market-sales fit."

Founders misuse the Henry Ford quote to justify ignoring user research. It wrongly equates a customer's underlying problem (demand), which is supply-agnostic, with their desire for a specific solution (supply). True innovation serves existing demand with a better supply, like a car fulfilling the need to travel.

The idea that startups find product-market fit and then simply scale is a myth. Great companies like Microsoft and Google continuously evolve and reinvent themselves. Lasting success requires ongoing adaptation, not resting on an initial achievement.

When a startup finally uncovers true customer demand, their existing product, built on assumptions, is often the wrong shape. The most common pattern is for these startups to burn down their initial codebase and rebuild from scratch to perfectly fit the newly discovered demand.

This reframes the fundamental goal of a startup away from a supply-side focus (building) to a demand-side focus (discovery). The market's unmet need is the force that pulls a company and its product into existence, not the other way around.

Using a child's toy analogy, demand is a pre-existing hole (e.g., a star shape) and your product is the block. Founders fail when they build a block and then search for a hole it fits. The real job is to first deeply understand the shape of the hole, then craft a block that fits it perfectly.