I’m always wary of 'Tugboat' companies, those with a great product but a broken distribution or model fit. This framework is a good filter for identifying 'Smooth Sailers.'
Super helpful refresh. What stands out to me is how AI speeds up the collapse of PMF. It feels like the window to adapt is way shorter now. Curious how you see teams handling that?
If we talk about AI and SaaS products it's important to point out that market is actively changing.
The main meta-question that is appropriate for any market and that changes the rules is "Could I actually build this product by myself fast and at low cost?".
The "Yes" answer becomes more frequent than "No".
So Entropy increases and it become much harder to reach PMF.
It become much harder to build a profitable and sustainable business if you are just a simple SaaS without a crucial unfair advantage (money, network, history).
Brian, this is an excellent update to the Four Fits, especially the way you show how AI compresses the PMF window.
I’d like to add a complementary perspective: many times what looks like Product-Market Fit is actually a subsidy illusion. Retention and enthusiasm can be strong, but if each new cohort burns more cash than it creates, that isn’t PMF, it’s manufactured demand.
In my recent article, When Love Isn’t Enough: The Real Test of Product-Market Fit, I argue that the real signal lies in cohort value trajectories.
Curious how you see this lens of profitability-by-cohort fitting into your Four Fits framework.
I’m always wary of 'Tugboat' companies, those with a great product but a broken distribution or model fit. This framework is a good filter for identifying 'Smooth Sailers.'
Super helpful refresh. What stands out to me is how AI speeds up the collapse of PMF. It feels like the window to adapt is way shorter now. Curious how you see teams handling that?
If we talk about AI and SaaS products it's important to point out that market is actively changing.
The main meta-question that is appropriate for any market and that changes the rules is "Could I actually build this product by myself fast and at low cost?".
The "Yes" answer becomes more frequent than "No".
So Entropy increases and it become much harder to reach PMF.
It become much harder to build a profitable and sustainable business if you are just a simple SaaS without a crucial unfair advantage (money, network, history).
Great another article on this topic: https://martinalderson.com/posts/ai-agents-are-starting-to-eat-saas/
Very helpful for startup founder who know only product market fit
Thoughtful but practical analysis, perfect for an ambitious early stage AI founder. Thanks Brian!
Brian, this is an excellent update to the Four Fits, especially the way you show how AI compresses the PMF window.
I’d like to add a complementary perspective: many times what looks like Product-Market Fit is actually a subsidy illusion. Retention and enthusiasm can be strong, but if each new cohort burns more cash than it creates, that isn’t PMF, it’s manufactured demand.
In my recent article, When Love Isn’t Enough: The Real Test of Product-Market Fit, I argue that the real signal lies in cohort value trajectories.
Curious how you see this lens of profitability-by-cohort fitting into your Four Fits framework.
https://rodrigofernandes.substack.com/p/when-love-isnt-enough-the-real-test
The key insight here is how these four must work in harmony to reinforce each other.
The move from SEO to Generative Engine Optimization (GEO) will continue to be a huge Channel and Model disruptor.
Great callout how AI’s unit economics work against traditional freemium models.