Glad you enjoyed the post. Would be interested to read as you publish your POV.
With regards to validating product economic fit, I have some ideas. “Five Forces” is a good starting point to think about the economics of a product category. The important thing to recognize is that when a company achieves PMF, it creates a disequilibrium in the forces.
For example, suppliers see the success and may decide to forward integrate. Regulators see the success and may decide to try to extend or clarify regulation. But most of all competitors (current and future) see the success and mobilize. In most cases, barriers to entry (i.e. limits on competition) become the primary determinant of PEF.
I wrote this up in more detail here.
It’s still an early draft, so will probably revise for better clarity.