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Apple doesn't actually care about smaller phone market. I'd argue they are as niche as iPod Touch market. The purpose of the mini is to improve Apple's ASP while still maintaining the tagline "starts at $699."
I doubt Apple would do things differently with the 13 lineup. The mini is there so people wanting a regular iPhone would spend $100 more on the regular model.
However, I do think once the cost drops for Apple, the mini form factor would be pushed down as the next gen SE, putting in single camera and LCD screen. They can advertise it as the same/larger screen than original SE with a more compact form factor.
My guess for this year's lineup.
SE2: $349
XR: $499 for 128GB
11: $599
12 mini: $599 or discontinued
12: $699
13 mini: $699
13: $799
The gap between the SE2 and XR is to assume for a slot for the rumored SE Plus next year, with SE 5G at $399, SE Plus 5G at $499, XR discontinued.