This strategy seems inspired by TikTok's approach for retaining new uploaders.

TikTok used to give new uploaders a visibility boost (i.e., an inflated number of likes and comments) on their first couple of uploads, to get them hooked on the the service.

In Anthropic/Claude's case, the strategy is (allegedly) to give new users access to the premium models on sign-up, and then increasingly cut the product with output from cheaper models.