The popularity for the Pro model appears to have caught Apple by surprise, as the company had reportedly prepared more stocks for the more affordable iPhone 12 on the assumption that demand would be higher for the entry-level 6.1-inch model.
The 6.1" NON-Pro is out-selling the 6.1" Pro, it's just that Apple thought the difference would be in the 3x-4x range, but in reality, it's ONLY in the 2x-3x range.
Apple is selling far more 6.1" Pro models than it expected, & far less 6.1" NON-Pro models than it expected.
Perhaps they simply priced the 6.1" NON-Pro too high !
The mini is the Wildcard, "could" out-sell both by a wide margin ! ... especially AFTER the Early Adopters get their 6.1" Pro.
BTW, the 6.1" Pro has 5.6 GB of DRAM, & it could be LPDDR5 ... still needs to be verified if it does OR not.
The 6.1" NON-Pro has the same 3.7 GB of DRAM as the 2019 Flagship iPhones.
The extra DRAM in this year's two Pro models is a BIG deal, & hasn't gotten its Day in the Sun, simply because few, if ANY, are actually using High Performance Apps anymore.