If PHK, DJB, <insert luminary> writes a post that comes across as clueless or flat out wrong, I'm going to read it and read it carefully. It does happen that <luminary> says dumb and/or incorrect things from time to time, but most likely there will be a very cool nugget of truth in there.

Regarding what PHK seems to be asking for, I think it's... linear addressing of physical memory, yes (because what else can you do?) but with pointer values that have attached capabilities so that you can dispense with virtual to physical memory mapping (and a ton of MMU TLB and page table hardware and software complexity and slowness) and replace it with hardware capability verification. Because such pointers are inherently abstract, the fact that the underlying physical memory address space is linear is irrelevant and the memory model looks more like "every object is a segment" if you squint hard. Obviously we need to be able to address arrays of bytes, for example, so within an object you have linear addressing, and overall you have it too because physical memory is linear, but otherwise you have a fiction of a pile of objects some of which you have access to and some of which you don't.