I wrote about it here https://medium.com/@franz.enzenhofer/about-targeted-list-lan... and played around with the model since then a lot.

As long as a company does not have organic growth. Meaning Referral (existing customers bring in new customers) > Churn (losing customers) there just is no scenario where it will end well for the company.

Adding investor money for paid growth is at best a halfway decent accelerator, at worst noise that hides the real performance of a company.