Also, this feels like it's forcing an external portfolio manager view on the internal operations of a startup. Nothing wrong with this - it's just odd to me.
Using the example from the linked material: surely if you can't swim, learning may be quite difficult.
PMF is really just a way to say "I de-risked these key areas", right? I think it does the best to encapsulate the idea of getting important things right but it's not the whole puzzle.
After PMF popularized, we had tons of people talking about Product/Channel Fit and Message/Market Fit, etc., since you need acquisition channels to work to fulfill demand and solid messaging to drive demand to begin with. Being lazy with channels is a big risk, IMO as a marketer. It's especially risky for bootstrapped startups to waste time on the wrong channels.
I don't feel that 99% of what people call PMF really exists. I don't think of AI/Blockchain startups ever had PMF at Series A stage and none of the hardware/bio startups ever do.