He did say "We may have some different versions, but they are not a new ASIC." This leaves the door open to a lot of other variants, including mobile, a cut down Navi 33 as a 7500 XT, and so on.
I agree that there are some holes in the lineup. I'd expect the 7700 XT to quickly drop below MSRP and so somewhat address that mid-range hole, but I can see AMD eventually releasing an even more cut-down Navi 32, unless next gen is already close enough that it won't be worth the bother.