This is from the assumption that "4K" and "8K" can only refer to 16:9 and 2160p. That isnt even remotely true for 4K so why should it apply to 8K. 4K UHD 16:9 isnt even 4000 pixels wide. The whole thing is a sham and consumers are always expected to be able to read more than just a headline marketing term to determine the real specs of a product.
Dont even get started on HDR TV's at 400 nits.