That’s not true. Apple sold a mini version for several generations and consistently the mini was always the worst performing version sales wise.

The "mini" lineup was never truly comparable to the flagship product. The specific deficiencies varied with the year but they were all missing an entire camera, and cameras are one of the single most important features of an iPhone.

The mini phones were significantly and arbitrarily gimped to mark them as a distinctly (and quite visibly) lower tier phone.