You’re right, I thought I remembered that article giving actual figures but instead it just handwavily says they didn’t sell many.

So, here is one that actually quotes a number, 3% of the whole iPhone lineup: macrumors.com/…/iphone-13-mini-unpopular-march-qu…

And another: cultofmac.com/…/iphone-13-mini-makes-up-a-tiny-pe…

And another, this one says 5% for some reason: notebookcheck.net/iPhone-13-Mini-sales-continue-t…

Either way 3% - 5% is a small number for Apple (or Samsung, or…) which might not justify making a small phone, but in absolute numbers, thats actually a lot of people! A smaller manufacturer should definitely be able to profitably fill this niche…