The business model I'm referring to is quite common nowadays: SAAS businesses offer free access to their product or service without any barriers, except for limits on usage. Once they have amassed a large user base, they abruptly close off access to the free version, eliminating the free trial option entirely. Examples of companies following this model include Midjourney, Kaiber, and potentially Figma in the near future.
It's important to note that this model differs from freemium, as freemium continues to offer a free version alongside premium options. It's also distinct from a timed demo (or trialware), which typically imposes time restrictions and provides users with a clear countdown. Instead, what I'm describing involves an unknown duration of free access that is suddenly and unexpectedly terminated or given minimal warning.
I have seen it before but can't remember where and Google is not helping (maybe not using the right search terms). The most similar name I have found is "Free-to-Paid Conversion Model", but it's not that, it was another name.
Additionally, I'm curious about the cognitive mechanism that plays a role in users accepting it in a significant proportion. I understand that it involves the Reward System, but I'm interested in knowing the exact specific mechanism among the various options of the Reward System.