I think the price change will be gradual, and will likely only be fully rolled out by 2023. Since you are intermixing with x86 Mac in between. But I think the lineup will look something like below by 2023.
$399 Mac mini / Nano. Most affordable Mac in Apple history ( previous lowest price was $499 Mac mini ). A12Z, 8GB RAM, 256GB.
$599. A14X or basically a better CPU, 16GB and 512GB SSD.
$799 12" Macbook ( SE? ), 8GB RAM Fanless Design, older gen CPU. Touch ID.
$999. 12" MacBook Air, 16GB RAM
$1099 14" MacBook Air
$1499 14" MacBook Pro, 16GB RAM, dGPU,
$1699 16" MacBook Pro
All the above are within Apple's standard 60% margin. I have no idea how Apple will go about the Desktop series given how the chips differs a lot in TDP profile. The MacBook Pro line also assumes the same SoC being used. Bumping up TDP cooling design.
I didn't read the full 7 pages but from a few summarise post there is this idea Apple wont lower price.
Apple went to Intel and Mac's price across the line were cheaper than its G5 era. It is not that Apple dont lower price. They dont lower *margins*. Unless there are some additional cost involves, for example Desktop Class TDP CPU that are spread only among the Mac models, Apple will just charge their margin and move as much product as possible.
I'll have a bit of a go with this, this lineup is probably a bit too neat and a lot I'm not sure of but I think something like this would be really good:
Airs get the Dell XPS treatment, super narrow bezels, probably rounded corners like the iPad Pro. New 13" takes on the price point of the 11" MacBook Air, 15" in at the current Air starting price, all with similar specs. This might be $100 too optimistic though. I'm saying they could share the vanilla iPad chip based on the competence of the A12Z but really not certain of that.
MacBook Air 13" (Approx size of 12" MacBook, no bezel display) - $899 (256GB/8GB/A14X 8 Core)
MacBook Air 15" (A little larger than 13" Air, no bezel display) - $999 (256GB/8GB/A14X 8 Core)
14" Pro takes over the current high end 13" Pro price point with similar specs. 16" Pro gets slightly cheaper, largely through deletion of dGPU and the cooling system for it. They use the rumoured 12 Core (8 Performance + 4 Efficiency) Mac chips.
MacBook Pro 14" - $1,799 (512GB/16GB/A14M 12 Core)
MacBook Pro 16" - $1,999 (512GB/16GB/A14M 12 Core)
iMacs really not sure on, tried to match the 24" to the MacBook Pro like the 21.5" currently sort of is, and a bit more oomph for the larger model. Keeping the user serviceable RAM on the larger model, though probably wishful thinking?
iMac 24" - $1,299 (256GB/8GB/A14M 12 Core)
iMac 32" - $1,799 (512GB/8GB/A14MX 16 Core + user serviceable RAM?)