[0] see: massive financial incentives, developer tooling to help maximize engagement, product design focused on extended use, notoriously useless screen time feature etc
[1] we don’t have exact mini sales, but estimates are they were around 6% of total iPhone sales (aka: low, but billions a year in revenue, enough to keep barring other incentives) - more revenue than many other Apple products or the SE, for example. Even if you’re Apple you don’t axe billions in revenue for nothing!