Product-market fit is no longer a stable milestone but a moving target that must be re-validated quarterly. Rapid advances in underlying AI models and swift changes in user expectations mean companies are on a constant treadmill to reinvent their value proposition or risk becoming obsolete.

Product-market fit isn't a sudden switch but a palpable shift in momentum. As a founder, you feel the change from pushing against the current (hard selling with little traction) to suddenly being pulled by it (easier sales, inbound interest). This directional change in velocity is the clearest signal that you're onto something.

This visceral analogy reframes product-market fit as an uncontrollable, overwhelming demand from the market. It's not just positive metrics; it's a state of being swarmed by customers. If you don't feel this intense 'market pull,' you haven't truly achieved it and must keep iterating.

In fast-moving industries like AI, achieving product-market fit is not a final destination. It's a temporary state that only applies to the current 'chapter' of the market. Founders must accept that their platform will need to evolve significantly and be rebuilt for the next chapter to maintain relevance and leadership.

PMF isn't a one-time achievement. Market shifts, like new technology or major events, can render your existing model obsolete. Successful companies must be willing to disrupt themselves and find new PMF to stay relevant.

Don't treat validation as a one-off task before development. The most successful products maintain a constant feedback loop with users to adapt to changing needs, regulations, and tastes. The worst mistake is to stop listening after the initial launch, as businesses that fail to adapt ultimately fail.

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.

Unlike traditional software where PMF is a stable milestone, in the rapidly evolving AI space, it's a "treadmill." Customer expectations and technological capabilities shift weekly, forcing even nine-figure revenue companies to constantly re-validate and recapture their market fit to survive.

PMF isn't a fixed state achieved once. It's a continuous process that must be re-evaluated at every stage of growth—from $1M to $1B. A company might have PMF for one scale but not for the next, requiring a constant evolution of strategy and product.